Case Studies & Application Stories

Pool Maintenance with the Myron L PoolPro

Posted by 4 Dec, 2014

TweetAnyone and everyone who is responsible for operating and maintaining a swimming pool or spa has to test, monitor, and control complex, interdependent chemical factors that affect the quality of water bathers are immersed in. Additionally, aquatic facilities operators must be familiar with all laws, regulations, and guidelines governing what these parameters should be. Why? […]

Anyone and everyone who is responsible for operating and maintaining a swimming pool or spa has to test, monitor, and control complex, interdependent chemical factors that affect the quality of water bathers are immersed in. Additionally, aquatic facilities operators must be familiar with all laws, regulations, and guidelines governing what these parameters should be.

Why? Because the worst breeding ground for any kind of microorganism is a warm (enough) stagnant pool of water. People plus stagnant water equals morbid illness. That’s why pools have to be circulated, filtered, and sanitized – with any number of chemicals or methods, but most frequently with chlorine compounds. However, adding chemicals that kill the bad microorganisms can also make the water uncomfortable, and in some cases unsafe, for swimmers. Additionally, if all the chemical factors of the water are not controlled, the very structures and equipment that hold the water and keep it clean are ruined.

So the pool professional must perform a delicate balancing act with all the factors that affect both the health and comfort of bathers and the equipment and structures that support this. Both water balance – or mineral saturation control – and sanitizer levels must constantly be maintained. This is achieved by measuring pertinent water quality factors and adding chemicals or water to keep the factors within acceptable parameters.

WATER BALANCE

Water is constantly changing. Anything and everything directly and indirectly affects the relationship of its chemical parameters to each other: sunlight, wind, rain, oil, dirt, cosmetics, other bodily wastes, and any chemicals you add to it. Balanced water not only keeps swimmers comfortable, but also protects the pool shell, plumbing, and all other related equipment from damage by etching or build-up and stains.

The pool professional is already well acquainted with pH, Total Alkalinity (TA), and Calcium Hardness (CH); along with Total Dissolved Solids (TDS) and Temperature, these are the factors that influence water balance. Water that is in balance is neither aggressive nor oversaturated.

Aggressive water lacks sufficient calcium to saturate the water, so it is hungry for more. It will eat anything it comes into contact with to fill its need, including the walls of your pool or spa or the equipment it touches. Over-saturated water cannot hold any more minerals, so dissolved minerals come out of solution and form scale on pool and equipment surfaces.

The pH of pool water is critical to the effectiveness of the sanitizer as well as the water balance. pH is determined by the concentration of Hydrogen ions in a specific volume of water. It is measured on a scale of 0-14, 0-7 being acidic and 7-14 being basic.

You must maintain the pH of the water at a level that assures the sanitizer works effectively and at the same time protects the pool shell and equipment from corrosion or scaling and the bathers from discomfort or irritation. If the pH is too high, the water is out of balance, and the sanitizer’s ability to work decreases. More and more sanitizer is then needed to maintain the proper level to kill off germs. Additionally, pH profoundly affects what and how much chemical must be added to control the balance. A pH of between *7.2 – 7.6 is desirable in most cases.

*As one of the most important pool water balance and sanitation factors, pH should be checked hourly in most commercial pools. Even if you have an automatic chemical monitor/controller on your system, you need to double-check its readings with an independent pH test. With saltwater pools, pH level goes up fast, so you need to check it more often. Tests are available that require reagents and subjective evaluation of color depth and hue to judge their pH. But different users interpret these tests differently, and results can vary wildly.

Myron L’s POOLPRO™ gives instant lab-accurate, precise, easy-to-use, objective pH measurements, invaluable in correctly determining what and how much chemical to add to maintain water balance and effective sanitizer residuals.

Total Alkalinity (TA) is the sum of all the alkaline minerals in the water, primarily in bicarbonate form in swimming pools, but also as sodium, calcium, magnesium, and potassium carbonates and hydroxides, and affects pH directly through buffering. The greater the Total Alkalinity, the more stable the pH. *In general, TA should be maintained at 80 – 120 parts per million (ppm) for concrete pools to keep the pH stable. Maintaining a low TA not only causes pH bounce, but also corrosion and staining of pool walls and eye irritation. Maintaining a high TA causes over-stabilization of the water, creating high acid demands, formation of bicarbonate scale, and may result in the formation of white carbonate particles (suspended solids), which clouds the water. Reducing TA requires huge amounts of effort. So the best solution to TA problems is prevention through close monitoring and controlling. Myron L’s Alkalinity Test Kit comes with sodium hydrogen sulphate tablets and a mixing/measuring vial to determine alkalinity in parts per million.

The other water balance parameter pool professionals are most familiar with is Calcium Hardness (CH). CH is the calcium content of the water and is measured in parts per million. Low CH combined with a low pH and low TA significantly increases corrosivity of water. As the water becomes more aggressive, the solubility of calcium carbonate also increases. This means that plaster and marcite pool finishes will deteriorate quickly because calcium carbonate is a major component of both plaster and marcite. Low CH also leads to corrosion of metal components in the pool plant, particularly in heat exchangers. Calcium carbonate usually provides a protective film on the surface of copper heat exchangers and heat sinks. This thin layer prevents much water-to-metal interaction but does not adversely affect the heating process. Without this protective layer caused by low CH, heat exchangers and associated parts can be destroyed prematurely. Strangely enough, as water temperature increases, solubility of calcium carbonate decreases. *The recommended range for most pools is 200 – 400 ppm. Calcium hardness should be tested at least monthly and has the least significant effect on the water balance when compared to pH and TA.

Total Dissolved Solids (TDS) is the sum of all solids dissolved in water. If all the water in a swimming pool was allowed to evaporate, TDS would be what was left on the bottom of the pool – like the white deposits left in a boiling pot after all the water has evaporated. Some of this dissolved material includes hardness, alkalinity, cyanuric acid, chlorides, bromides, and algaecides. TDS also includes bather wastes, such as perspiration, urine, and others.

TDS is often confused with Total Suspended Solids (TSS). But TDS has no bearing on the turbidity, or cloudiness, of the water, as all the solids are truly in solution. It is TSS, or undissolved, suspended solids, present in or that precipitate out of the water that make the water cloudy.

High TDS levels do affect chlorine efficiency, algae growth, and aggressive water, but only minimally. TDS levels have the greatest bearing on bather comfort and water taste – a critical concern for commercial pool operators. At levels of over 5,000ppm, people can taste it. At over 10,000ppm bather towels are scratchy and mineral salts accumulate around the pool and equipment. Still some seawater pools comfortably operate with TDS levels of 32,000ppm or more.

As methods of sanitization have changed, high TDS levels have become more and more of a problem. *The best course of action is to monitor and control TDS by measuring levels and periodically draining and replacing some of your mature water with new, lower TDS tap water. This is a better option than waiting until you must drain and refill your pool, which is not allowed in some areas where water conservation is required by law. However, you can also decrease TDS with desalinization equipment as long as you compensate with Calcium Hardness. (Do not adjust water balance by moving pH beyond 7.8.)

Regardless, you do need to measure and compensate for TDS to get the most precise saturation index and adjust your pH and Calcium Hardness levels accordingly. *It is generally recommended that you adjust for TDS levels by subtracting one tenth of a saturation index unit (.1) for every 1,000ppm TDS over 1,000 to keep your water properly balanced. When TDS levels exceed 5,000ppm, it is recommended that you subtract half of a tenth, or one twentieth of unit (.05) per 1,000ppm. And as the TDS approaches that of seawater, the effect is negligible.

Hot tubs and spas have a more significant problem with TDS levels than pools. Because the swimmer load is relatively higher, more chemicals are added for super-chlorination and sudsing along with a higher concentration of bather wastes. The increased electrical conductance that high TDS water promotes can also result in electrolysis or galvanic corrosion. Every hot water pool operator should consider a TDS analyzer as a standard piece of equipment.

A TDS analyzer is required to balance the water of any pool or spa in the most precise way. Myron L’s POOLPRO and POOLMETER™ immediately display TDS levels to correctly calculate your water’s saturation index and to ensure you take corrective action before TDS gets out of hand.

Temperature is the last and least significant factor in maintaining water balance. As temperature increases, the water balance tends to become more basic and scale producing. Calcium carbonate becomes less soluble, causing it to precipitate out of solution. As temperature drops, water becomes more corrosive.

In addition to helping determine water balance, temperature also affects bather comfort, evaporation, chlorination, and algae growth (warmer temperatures encourage growth). Myron L’s POOLPRO also precisely measures temperature to one tenth of a degree at the same time any other parameter is measured.

The formula for determining water balance is called the Langlier Index, or Saturation Index. It is determined by the following formula:

SI= (pH + TF + CF + AF ) – 12.1

Where TF is the temperature, CF is Calcium Hardness, and AF is Total Alkalinity adjusted for temperature. 12.1 is the Total Dissolved Solids constant. Consult appropriate conversion charts to obtain the correct values for each variable.

– An index between -0.5 and +0.5 is acceptable pool water.
– An index of more than +0.5 is scale-forming.
– An index below -0.5 is corrosive.

pH, Total Alkalinity, and Calcium Hardness are the big three contributors to water balance. *Pool water will often be balanced if these factors are kept within the recommended ranges.

SANITATION

The most immediate concern of anyone monitoring and maintaining a pool is the effectiveness of the sanitizer – the germ-killer. There are many types of sanitizers, the most common being chlorine in swimming pools and bromine in hot tubs and spas. The effectiveness of the sanitizer is directly related to the pH and, to a lesser degree, the other factors influencing water balance.

To have true chemical control, you need to monitor both the sanitizer residual and the pH and use that information to chemically treat the water – that’s where ORP comes in. ORP indicates the ability of oxidizers to burn up organic matter in the water, which means your water is clean and sanitary. There are colorimetric tests used to determine the amount of effective sanitizer for chlorine and other elements, but none is as objective and precise in determining the total killing power of all sanitizers as ORP.

ORP stands for Oxidation Reduction Potential (or REDOX) of the water and is measured in millivolts (mV). The higher the ORP, the greater the killing power of all sanitizers, not just free chlorine, in the water. ORP is the only practical method available to monitor sanitizer effectiveness. Thus, every true system of automatic chemical control depends on ORP to work.

The required ORP for disinfection will vary slightly between disinfecting systems and is also dependent on the basic water supply potential, which must be assessed and taken into account when the control system is initialized. *650mV to 700 – 750mV is generally considered appropriate.

Electronic controllers can be inaccurate and inconsistent when confronted with certain unique water qualities, so it is critical to perform manual testing with separate instrumentation. *For automatic control dosing, it is generally recommended that you manually test pH and ORP prior to opening and then once during the day to confirm automatic readings.

*Samples for confirming automatic control dosing should be taken from a sample tap strategically located on the return line as close as possible to the probes in accordance with the manufacturer’s instructions. If manual and automatic readings consistently move further apart or closer together, you should investigate the reason for the difference.

ORP readings can only be obtained with an electronic instrument. Myron L’s POOLPRO provides the fastest, most precise, easy-to-use method of obtaining ORP readings to check the effectiveness of the sanitizer in any pool or spa. This is the best way to determine how safe your water is at any given moment.

SALTWATER SANITATION

A relatively new development, saltwater pools use regular salt, sodium chloride, to form chlorine with an electrical current much in the same way liquid bleach is made. As chlorine – the sanitizer – is made from the salt in the water, it is critical to maintain the salt concentration at the appropriate levels to produce an adequate level of sanitizer. It is even more important to test water parameters frequently in these types of pools and a spa, as saltwater does not have the ability to respond adequately to shock loadings (super-chlorination treatments).

Most saltwater chlorinators require a *2,500 – 3,000ppm salt concentration in the water (though some may require as high as 5,000-7,000ppm). This can barely be tasted, but provides enough salt for the system to produce the chlorine needed to sanitize the water.

(It is important to have a good stabilizer level – *30 – 50 ppm – in the pool, or the sunlight will burn up the chlorine. Without it, the saltwater system may not be able to keep up with the demand regardless of salt concentration.)

Taste and salt shortages are of little concern to seawater systems that maintain an average of 32,000ppm. In these high-salt environments, you need to beware of corrosion to system components that can distort salt level and other parameter readings.

Additionally, incorrect salt concentration readings can occur in any saltwater system. The monitoring/controlling components can and do fail or become scaled — sometimes giving a false low salt reading. Thus, you must test manually for salt concentration with separate instrumentation before adding salt.

You must also test salt concentration manually with separate instrumentation to re-calibrate your system. This is critical to system functioning and production of required chlorine. Myron L’s POOLPRO conveniently tests for salt concentration at the press of the button as a check against automatic controller systems that may have disabled equipment or need to be re-calibrated.

As you can see, there are many factors affecting the comfort and sanitation of pool and spa water and the functioning of the equipment and structures that hold it, and no one instrument or method can be used to determine ALL of them, but Myron L’s POOLPRO gives you the most precise and comprehensive water testing instrument in one easy-to-use, handheld waterproof unit. Where precision counts, we’ve got you covered.

RECORD KEEPING – What to do with all those measurements …

Now that you have the data, you have to correctly transcribe, evaluate, and report it to the proper government agencies, or at least archive it as permanent record of proper compliance to whatever regulations apply to your pool or spa. (As if sanitizing and balancing the chemistry of the water wasn’t enough.)

*It is recommended (by the World Health Organization and other entities) that data handling be done objectively and that data be recorded in a common format and in the most accurate way. Also, data should be stored in more than one permanent location and made available for future analysis. *Most municipalities require commercial aquatic facilities to keep permanent records onsite and available for inspection at any time.

*Myron L’s POOLPRO makes it easy to comply with data record requirements. The POOLPRO is an objective means to test ORP, pH, TDS, temperature and the mineral/salt content of any pool or spa. You just rinse and fill the cell cup by submerging the waterproof unit and press the button of the parameter you wish to measure. You immediately get a standard, numerical digital readout – no interpretation required – eliminating all subjectivity. Up to 100 date-time-stamped readings can be stored in memory and then later transferred directly to a computer using our BluDock™ accessory package. You just set the unit on the Bludock and download the data to the computer. The user never touches or tampers with the data, reducing the potential for human error in transcription. The data can then be imported into any program necessary for record-keeping and analysis. *The Bludock is the fastest, easiest, best way to keep records that comply with governing standards.

Myron L Company’s POOLPRO is SIMPLY the best.

*Consult your governing bodies for specific testing, chemical concentrations, and all other guidelines and requirements. The ranges suggested here are meant as general examples.
Myron L Company assumes no responsibility for lack of compliance to specific regulations governing the testing and control of parameters in your pool and/or spa.

Categories : Application Advice, Case Studies & Application Stories, Product Updates, Science and Industry Updates, Technical Tips

How an Ultrameter II 6P Helps Map Fluoride Contamination in Ghana: MyronLMeters.com

Posted by 7 Jul, 2014

TweetThe need for safe drinking water in rural Ghana inspired Katherine Alfredo, a graduate student at the University of Texas at Austin to propose a project for a Fulbright Fellowship. The purpose of the fellowship was to map the extent of the fluoride concentration in the Bongo District of the Upper Eastern Region for use […]

The need for safe drinking water in rural Ghana inspired Katherine Alfredo, a graduate student at the University of Texas at Austin to propose a project for a Fulbright Fellowship. The purpose of the fellowship was to map the extent of the fluoride concentration in the Bongo District of the Upper Eastern Region for use by local authorities and eventually use the data collected in the development of a cost-effective defluoridation filter for existing capped wells.

In rural areas, groundwater is plentiful, but natural geographic contamination by inorganic contaminants like iron, manganese and fluoride render government sponsored boreholes useless. Fluoride in the Upper East, Upper West and Northern regions of Ghana often exceeds the general WHO recommended limit of 1.5 mg/liter.

Katherine began her research by observing and recording local water usage habits. She conducted borehole water usage counts on centrally and non-centrally located borehole sites tracking the quantity of water collected daily. Coupling this data with familial compound water usage surveys she was able to begin understanding the volumetric demand placed on each borehole daily and how that volume translates to the household level.

A one-liter sample of water was retrieved for testing and used for all the water quality tests. An aliquot of the sample water was placed in an Ultrameter II 6P to measure pH, ORP, conductivity, total dissolved solids and temperature.

Conductivity readings from the Ultrameter II will be used to simulate influent water containing excessive levels of fluoride in Katherine’s laboratory. Using Bongo as a design test case, Katherine plans to adjust the ionic strength of her synthetic influent to reflect that seen in the Bongo District.

Ultrameter II TDS readings were used as a quality indicator of water as it was dispensed from a borehole. The amount of all dissolved solids is important in determining the potential for interference and competition for adsorption sites on the aluminum adsorbents. Preventing any ions from competing for active sites on alumina surfaces will greatly increase the efficiency of filtration.

ORP readings taken by the Ultrameter II gave a good indicator of the general biological activity in the water. Additional testing was performed using two 2 mL tubes filled with sample water to measure nitrate/nitrite and ammonia using test strips. In another 2 mL tube a 1:1 dilution of the sample was created using distilled water to measure alkalinity using test strips.

Using a 0.45 micron filter, a 30 mL or 60 mL sterile plastic bottle was completely filled for fluoride concentration testing later in the laboratory.

Each capped borehole, new borehole, or nonfunctional borehole that was visited had its corresponding borehole identity recorded in a handheld GPS device. After each governance was covered, eight capped boreholes were chosen for water quality testing to be compared to the nearby functional boreholes.

At the time of Katherine’s departure, she had reported the pH and fluoride concentration of each well to the two water and sanitation government agencies in the Bongo area—The Community Water and Sanitation Agency and The Bongo District Assembly Water and Sanitation Team.

Katherine continues to analyze data recorded in Ghana and experiment with cost-effective solutions for fluoride removal in rural communities.

Find out more about the Ultrameter II 6P.

Categories : Case Studies & Application Stories

Expert Manages Storm Water Discharge in Active Construction Sites With Ultrameter II 6P: MyronLMeters.com

Posted by 7 Jul, 2014

Tweet Mike Alberson, an expert in storm water pollution prevention, uses the Myron L Ultrameter II 6P to meet new and existing state and federal requirements for storm water monitoring. He checks for the presence of pollutants by testing the levels of total dissolved solids (TDS) and conductivity. He also tests storm water pH levels […]

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Mike Alberson, an expert in storm water pollution prevention, uses the Myron L Ultrameter II 6P to meet new and existing state and federal requirements for storm water monitoring. He checks for the presence of pollutants by testing the levels of total dissolved solids (TDS) and conductivity. He also tests storm water pH levels in accordance with NPDES guidelines implemented in California in 2010 that mandate pH testing for all Risk Level 2 and 3 sites.

Though TDS and conductivity do not indicate the presence of any specific contaminant, monitoring these parameters is a good way to determine an increase in the concentration of dissolved chemical constituents generally. High conductivity or TDS levels are a red flag to Alberson to investigate potential sources of pollution.

Chemicals used in landscaping, such as herbicides, pesticides and fertilizers, as well as materials such as cement, can all potentially dissolve into storm water runoff. Additionally, acidic or basic pollutants impact the quality of water by altering the pH of the runoff. Monitoring is required because altering the pH alters the types and amounts of all chemical constituents in runoff and, thereby, its toxicity. Changes in pH also impact the ecosystem directly when they exceed the narrow range required by biota to live in the receiving waters. The new California NPDES requirements have set a pH range limit of 6.5 to 8.5 pH Units

The State Water Quality Board’s overall goal in implementing increased monitoring and reporting requirements is to evaluate the effectiveness of Best Management Practices (BMPs) on effluent pollution and the impact that construction activities have on receiving waters. Developers and inspectors like Alberson are continually challenged with preventing potential pollutants from leaving the project sites, and when that happens, they need to remediate any adverse affects on the environment.

As a prerequisite to construction, the Developer of Plan must generate and gain approval of BMPs and Storm Water Pollution Prevention Plans (SWPPPs) which take into account the nature of the project’s building schedule, phasing of the project, building materials, the projected rainfall, the percentage of impervious cover on the project and the impact that potential storm water runoff could have on receiving waters.  The plans must also address the required monitoring and critical indicators of specific pollutants projected to discharge from the project site.

The site storm water inspector has to ensure that the necessary BMPs are implemented throughout the length of the project, as defined by the project SWPPP plan, which addresses project-specific site conditions and risk level determinations.  Alberson uses the meter frequently on Barnhart Balfour Beatty projects as most fall into a category of Risk Level 2, which now requires pH monitoring along during a rain event of 0.5 in. or more.

New California requirements have required all SWPPP developers and inspectors to be certified by the state since Sept. 2, 2011 via a special course given by designated State Trainers of Record (TOR). Alberson is designated as a TOR and offers California’s new Qualified SWPPP Practitioner and Qualified SWPPP Developers courses.

As a trainer, Alberson passes on knowledge gained from his own experience. Through the years, he has seen inspectors send water samples off to laboratories for analysis, the results of which would not be known for up to two weeks. In addition, the pH of these samples would change in the time it took to get the samples to the labs for analysis. Alberson now trains developers and inspectors to use the Myron L Ultrameter II to immediately measure pH, thereby ensuring storm water runoff on project sites is precisely monitored for potential pollutants in real time.

In his own work as an inspector, Alberson has used the Myron L Ultrameter II to respond to potential pollution issues as they arise. For example, at Barnhart Balfour Beatty’s Otay Ranch Village #6 Elementary School project in Otay Mesa, Calif., he developed a remediation solution that prevented environmental contamination from high pH runoff resulting from a required lime treatment of the campus soil. By performing onsite testing following a rain event, Alberson was able to determine the potential runoff had a pH level of 12.5.  He decided to immediately utilize a retention pond with carbon dioxide percolation control techniques. His remediation tactic worked using the meter to continuously monitor the pH until it was at a level acceptable for release into the receiving waters.

Categories : Case Studies & Application Stories

Real-Time Field Water Analysis with an Ultrameter III 9P: Myron L Meters

Posted by 30 Apr, 2014

Tweet The Ultrameter III 9P Titration Kit allows for fast, accurate alkalinity, hardness & LSI titrations in the field. The Ultrameter III 9P is based on the tried and tested design of the Ultrameter II 6P and measures conductivity, resistivity, TDS, pH, ORP, free chlorine and temperature quickly and accurately. The 9P also features new […]

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The Ultrameter III 9P Titration Kit allows for fast, accurate alkalinity, hardness & LSI titrations in the field.

The Ultrameter III 9P is based on the tried and tested design of the Ultrameter II 6P and measures conductivity, resistivity, TDS, pH, ORP, free chlorine and temperature quickly and accurately. The 9P also features new parameters that allow the user to perform titrations in the field. The Ultrameter III 9P has a unique method of performing alkalinity, hardness and LSI titrations that makes field monitoring fast and feasible.

How does it work?

The 9P titrations are based on conductometric titration methods that are possible with the 9P’s advanced conductivity cell and microprocessor based design. Titrations are chemically equivalent to standard methods using colorimetric techniques, but replace color change identification of equivalence points with changes in conductivity, thereby replacing a subjective, qualitative assessment with a quantitative one. This means the instrument determines the equivalence point instead of the user and the method of analyzing the equivalence point is objective, rather than subjective.

What is a conductometric titration?

A conductometric titration is performed just like a colorimetric titration, only the equivalence point is determined by a change in conductivity rather than a change in color. This is based on the fact that changes in ionic concentration that occur as constituents react with reagents change the electrical conductivity of the solution.

A simple example can be given of the titration of a strong acid with a strong base. The acid solution, before the addition of the base, has a very high conductance owing to the concentration and mobility of the small hydrogen ions.

With the addition of the base, the hydroxide reacts with the hydrogen to form water, thus reducing the hydrogen ion concentration and effectively lowering the conductivity of the solution. The conductivity continues to decrease until all the hydrogen ions are consumed in the reaction, but then sharply increases with the next addition of base, which contains highly conductive hydroxide ions. The solution conductivity then continues to increase with each base addition. The equivalence point in this example would be a clearly defined minimum point of lowest conductivity (see Figure 2).

Not all solutions will give a plot with an equivalence point that is as easy to distinguish as the sharp upturn found in a strong acid-base titration, however. The 9P plots several reagent additions beyond any changes in conductivity and matches the derived curve to the behavior of solutions of known concentration.

Is a conductometric titration a standard method?

(Standard method comparison to methods listed in the Standard Methods for the Examination of Water and Wastewater published by the American Public Health Assn., the American WaterWorks Assn. and the Water Environment Assn.)

Myron L’s conductometric titration methods are chemically equivalent to standard methods that use the same procedure, but with pH indicators. That means that they use the same reagents in the same sequence with the same theoretical approach. The difference lies in the 9P’s ability to determine the equivalence point based on numerical data, rather than subjective observation of a color change.

The alkalinity titration is modeled after standard method 2320. The sample is titrated with sulfuric acid and conductivity changes are recorded at each titration point.

The hardness titration is modeled after standard method 2340. To reduce the affects of high alkalinity in the form of bicarbonate, acid is first added to the sample. This shifts the bicarbonate toward carbonic acid, then carbon dioxide (reference the carbonic acid equilibrium), which is gassed off the sample. The sample is buffered above pH 10 (effectively pH 12) by the addition of sodium hydroxide. EDTA reagent is then added incrementally, with conductivity measured after each addition.

The LSI titration uses a simplified version of the thermodynamic equations for the determination of the scaling tendency of water developed in 1936 by Dr. Wilfred Langelier. The user simply titrates for alkalinity and hardness, then measures pH and temperature, and the 9P generates the saturation index value automatically.

Conductometric vs. Colorimetric

The benefits of determining the equivalence points by conductometric titrations are that the user does not have to interpret any results. The 9P does it for you using objective measurements. And the 9P is a faster method. For example, a typical colorimetric titration for hardness can take up to 30 drops of reagent, while the 9P method for the same concentration only requires six to eight drops. Colorimetric distinctions are sometimes hard to make, as well, especially when adding reagents drop by drop while trying to carefully observe the precise point at which the color changes—and that can lead to inaccurate data. This is especially true in colored or turbid solutions.

The conductometric method can also be used with very dilute solutions or for solutions for which there is no suitable indicator. The conductometric titration method gives you empirical results that are calculated for you, eliminating potential sources of error. And the measurements can be stored in memory for later data transfer using the optional U2CI software and bluDock Bluetooth hardware installed on the 9P . This makes data analysis and reporting seamless.

What else can the Ultrameter III 9P do?

Alkalinity, hardness, pH and temperature values used to compute the saturation index of a sample can be manipulated in the LSI Calculator function, allowing you to perform on the spot analysis of water balance scenarios. You can use historical or theoretical data to populate the required values in the calculator.

And the 9P titration kit comes with all required accessories, reagents, and calibration solutions (see Figure 6). Streamline your field testing with an Ultrameter III 9P from MyronLMeters, where you can save 10% when you order online.

Myron L Meters is the premier online retailer of accurate, reliable, and easy-to-use Myron L meters like the Ultrameter III 9P.  Save 10% when you order online at MyronLMeters.com. Find out more about the Ultrameter III 9P in our Myron L Meters – Ultrameter III 9P Titration Kit Overview video.

 

Categories : Case Studies & Application Stories, Product Updates

FDA Warning: MyronLMeters.com

Posted by 14 Apr, 2014

Tweet  FDA Warning Are You FDA Compliant? In recent news “A warning letter sent to (a dialysis clinic operator) by the US Food and Drug Administration (FDA)”… “FDA said the company needs to take “prompt action to correct the violations addressed in the letter,” and that failure to comply could lead to more serious regulatory […]

 

FDA Warning

Are You FDA Compliant?

In recent news “A warning letter sent to (a dialysis clinic operator) by the US Food and Drug Administration (FDA)”… “FDA said the company needs to take “prompt action to correct the violations addressed in the letter,” and that failure to comply could lead to more serious regulatory enforcement actions, up to and including seizure, injunction and civil penalties.”

Are your devices FDA 510K compliant? Click here to learn about the FDA 510K compliant D-6 and D-4 from Myron L Meters. Order online and save 10%. ‘Digital Dialysate Meter D-6

                                   
D-6               Click to view product details                 D-4
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Categories : Case Studies & Application Stories, Company News

Measuring ORP: MyronLMeters.com

Posted by 12 Apr, 2014

Tweet Ultrapen PT3 ORP tester Though the measurement of free chlorine concentration is often indicated for the disinfection of water and disinfectant byproduct control, there is a better way. Because free chlorine works through oxidation, ORP instrumentation can be used to monitor and control its effectiveness. ORP measures the actual oxidation power of the solution, […]



Ultrapen PT3 ORP tester Ultrapen PT3 ORP tester



Though the measurement of free chlorine concentration is often indicated for the disinfection of water and disinfectant byproduct control, there is a better way. Because free chlorine works through oxidation, ORP instrumentation can be used to monitor and control its effectiveness. ORP measures the actual oxidation power of the solution, specifically the strength and number of oxidation and reduction reactions in solution. This yields a clear picture of the efficacy of the chlorine present, regardless of the concentration or ratio of chlorine species in solution.
Measuring ORP directly reflects the sanitizing power of free chlorine or any other oxidizing or reducing chemicals. The measurement of ORP is precise, empirical and requires no user interpretation, making it ideal for water quality and industrial process control.
What is ORP?
ORP stands for Oxidation Reduction Potential, sometimes called REDOX. ORP is a differential measurement of the mV potentials built up when electrodes are exposed to solutions containing oxidants and reductants. ORP describes the net magnitude and direction of the flow of electrons between pairs of chemical species, called REDOX pairs.
In a REDOX pair, one chemical loses electrons while the other chemical gains electrons. The chemical in the REDOX exchange that acquires electrons is called the oxidant (HOCL, OCl-, ClO2, bromine, hydrogen peroxide, etc.). The chemical in the REDOX exchange that gives up electrons is called the reductant (Li, Mg2, Fe2+, Cr2, etc.). Oxidants acquire electrons through the process of reduction, i.e., they are reduced. Reductants lose their electrons through the process of oxidation, i.e., they become oxidized.
How is ORP measured?
ORP sensors are basically two electrochemical half-cells: A measurement electrode in contact with the solution being measured and a reference electrode in contact with a reservoir of highly concentrated salt solution.
When the solution being measured has a high concentration of oxidizers, it will accept more electrons than it loses so that the measurement electrode develops a higher electrical potential than the reference electrode. A voltmeter placed in line with the two electrodes will display this difference in potential between the two electrodes. Once the entire system reaches equilibrium, the resulting net potential difference represents the ORP. A positive reading indicates an oxidizing solution, and a negative reading indicates a reducing solution. The more positive or negative the value, the more powerful the oxidants or reductants, the greater their concentrations or both.
What does ORP measure?
ORP can be used to determine the efficacy of chemical disinfectants that work via the oxidation or reduction of the structures of microbial contaminants. For example, chlorine, an oxidant, will strip electrons from the negatively charged cell walls of some bacteria. Because ORP measures the total chemical activity of a solution, ORP measures the total efficacy all oxidizing and reducing disinfectants in solution: Hypochlorous acid, monochloramine, dichloramine, hypobromous acid, sodium hypochlorite, UV, ozone, peracetic acid, bromochlorodimethylhydantoin, etc.
ORP indicates the effectiveness of only those disinfectants that work through oxidation and reduction. ORP cannot be used to detect the presence of any one particular chemical or chemical species. Nor can it alone be used to determine the concentration of a known species of chemical in solution. This means that although ORP is the best way to know whether or not your sanitizer is working, it can’t tell you how much or what kind of sanitizer is working.
What factors affect ORP measurement?
While the accuracy of ORP sensors is relatively stable, which is why they do not require calibration, there are factors that affect their response time. Changes in temperature can affect response times by altering the kinetic rates of the reactions being measured, for example. Low temperatures reduce the kinetic rates and lengthen sensor response times.
The condition of the electrode will also alter response times by changing the “exchange current density” (the amount of electrons exchanged per unit area of exposed electrode). The lower the exchange current density, the more sluggish the sensor response. The typical measurement electrode is made from pure platinum (Pt) because it is a noble metal and, therefore, highly unreactive, i.e., the potential being measured is most likely due to the activity of the chemicals in the water and not reactions between the solution and the Pt itself. Even though Pt is a noble metal, it will form a thin oxide layer on the surface of the platinum when exposed to dissolved oxygen. This oxide layer facilitates the ORP measurement when it is very thin, one molecule thick, by attracting, or “adsorbing,” hydrolyzed oxidant or reductant molecules to the surface of the electrode.
Unfortunately, when the oxide layer becomes more than one molecule thick, the resulting lowered exchange current density offsets this benefit. Also, the adsorbed molecules cause a “memory effect.” If a sensor is placed in a less oxidizing solution after measuring a more oxidizing solution, it can take a very long time for the sensor to equilibrate to the new sample. Though the sensor response time is much slower, the final ORP reading will be the same.
ORP electrodes never require recalibration because there is no drift in zero point (as is the case with pH sensors). Any deviation from expected readings is most likely due to surface contamination of the electrodes or buildup of the oxide layer, both of which can easily be remedied by cleaning with a light abrasive, such as Softscrub®. Exposing the sensor to an “ORP conditioning solution” will help reduce the memory effect due to adsorption.
Can ORP be used as a surrogate parameter for free chlorine?
Yes. ORP measures the oxidizing power and, therefore, the actual residual sanitizing strength of the solution being tested. Simply counting how much chlorine is present is misleading because certain changes in water chemistry, such as pH or the addition of cyanuric acid, dramatically alter the oxidizing power of chlorine and, therefore, its efficacy, without changing how much chlorine is present.
When correlated with established disinfection control parameters, measurements and bacterial plate counts, this type of measurement gives a very accurate picture of the sanitizing activity. For this correlation to be valid, the water undergoing treatment must be characterized so that all chemical constituents are known. The pH and temperature values should be reported and held constant. ORP will report an empirical value or a hard number that indicates how active the sanitizer is. However, you have to make certain that microbial contamination is responding to the treatment. Once a correlation is established in a stable system, ORP is a very efficient and effective way to monitor microbial control.
ORP has long been used in bathing waters as the only means for automatic chemical dosing. In fact, the World Health Organization (WHO) suggests an ORP value of between 680-720 mV, depending on the sensor and the particular context, for safe bathing water. In the disinfection of drinking water, an ORP value of ~800 mV is required for oocyst inactivation.
For the purpose of pretreatment screening to detect chlorine levels prior to contact with chlorine-sensitive RO membranes, influent must first be screened to determine which chemicals besides chlorine are present that contribute to the ORP value. With these interferants characterized and pH and temperature held constant, ORP can be correlated to specific sanitizer concentrations, such as chlorine, in their known forms. Some manufacturers of RO membranes and other water quality treatment equipment will also specify an ORP tolerance value for prescreening and influent control. The same holds true of effluent screening.
Why ORP?
ORP is a faster, simpler empirical measurement than titration with DPD or other methods, and in many cases it gives the most accurate picture of the effect of all oxidizing and reducing chemicals in solution. No in-depth knowledge or training is required to obtain accurate repeatable results. User error is virtually eliminated because ORP readings require no subjective, visual interpretation, nor do they require calibration.
Using ORP disinfectant control can be automated because the measurement produces an electrical signal that can trigger switches when outside established control parameters. And ORP sensors are relatively low-maintenance. If you’re not using ORP to monitor and control chemical additions that work through REDOX, you should. You’ll save yourself time, hassle and money.
Myron L Meters is the premier internet retailer of accurate, reliable Myron L meters like the Ultrapen PT3, ORP pen tester.
Categories : Case Studies & Application Stories

DEIONIZED WATER APPLICATIONS: MyronLMeters.com

Posted by 11 Apr, 2014

TweetYears ago, high purity water was used only in limited applications. Today, deionized (Dl) water has become an essential ingredient in hundreds of applications including: medical, laboratory, pharmaceutical, cosmetics, electronics manufacturing, food processing, plating, countless industrial processes, and even the final rinse at the local car wash. THE DEIONIZATION PROCESS The vast majority of dissolved […]

Years ago, high purity water was used only in limited applications. Today, deionized (Dl) water has become an essential ingredient in hundreds of applications including: medical, laboratory, pharmaceutical, cosmetics, electronics manufacturing, food processing, plating, countless industrial processes, and even the final rinse at the local car wash.

THE DEIONIZATION PROCESS
The vast majority of dissolved impurities in modern water supplies are ions such as calcium, sodium, chlorides, etc. The deionization process removes ions from water via ion exchange. Positively charged ions (cations) and negatively charged ions (anions) are exchanged for hydrogen (H+) and hydroxyl (OH-) ions, respectively, due to the resin’s greater affinity for other ions. The ion exchange process occurs on the binding sites of the resin beads. Once depleted of exchange capacity, the resin bed is regenerated with concentrated acid and caustic which strips away accumulated ions through physical displacement, leaving hydrogen or hydroxyl ions in their place.

DEIONIZER TYPES
Deionizers exist in four basic forms: disposable cartridges, portable exchange tanks, automatic units, and continuous units. A two-bed system employs separate cation and anion resin beds. Mixed-bed deionizers utilize both resins in the same vessel. The highest quality water is produced by mixed-bed deionizers, while two-bed deionizers have a larger capacity. Continuous deionizers, mainly used in labs for polishing, do not require regeneration.

TESTING Dl WATER QUALITY
Water quality from deionizers varies with the type of resins used, feed water quality, flow, efficiency of regeneration, remaining capacity, etc. Because of these variables, it is critical in many Dl water applications to know the precise quality. Resistivity/ conductivity is the most convenient method for testing Dl water quality. Deionized pure water is a poor electrical conductor, having a resistivity of 18.2 million ohm-cm (18.2 megohm) and conductivity of 0.055 microsiemens. It is the amount of ionized substances (or salts) dissolved in the water which determines water’s ability to conduct electricity. Therefore, resistivity and its inverse, conductivity, are good general purpose quality parameters.

Because temperature dramatically affects the conductivity of water, conductivity measurements are internationally referenced to 25°C to allow for comparisons of different samples. With typical water supplies, temperature changes the conductivity an average of 2%/°C, which is relatively easy to compensate. Deionized water, however, is much more challenging to accurately measure since temperature effects can approach 10%/°C! Accurate automatic temperature compensation, therefore, is the “heart’ of any respectable instrument.

RECOMMENDED MYRON L METERS
Portable instruments are typically used to measure Dl water quality at points of use, pinpoint problems in a Dl system confirm monitor readings, and test the feed water to the system. The handheld Myron L meters have been the first choice of Dl water professionals for many years. For two-bed Dl systems, there are several usable models with displays in either microsiemens or ppm (parts per million) of total dissolved solids. The most versatile instruments for Dl water is the 4P or 6PFCE Ultrameter II™, which can measure both ultrapure mixedbed quality water and unpurified water. It should be noted that once Dl water leaves the piping, its resistivity will drop because the water absorbs dissolved carbon dioxide from the air. Measuring of ultrapure water with a hand-held instrument requires not only the right instrument, but the right technique to obtain accurate, repeatable readings. Myron L meters offer the accuracy and precision necessary for ultrapure water measurements.

Inline Monitor/controllers are generally used in the more demanding Dl water applications. Increased accuracy is realized since the degrading effect of carbon dioxide on high purity water is avoided by use of an in-line sensor (cell). This same degradation of ultrapure water is the reason there are no resistivity calibration standard solutions (as with conductivity instruments). Electronic sensor substitutes are normally used to calibrate resistivity Monitor/controllers.

Myron L Meters carries a variety of inline instruments, including resistivity Monitor/controllers designed specifically for Dl water. Seven resistivity ranges are available to suit any Dl water application: 0-20 megohm, 0-10 megohm, 0-5 megohm, 0-2 megohm, 0-1 megohm, 0-500 kilohm, and 0-200 kilohm. Temperature compensation is automatic and achieved via a dual thermistor circuit. Monitor/controller models contain an internal adjustable set point, piezo alarm connectors and a heavy-duty 10 amp relay circuit which can be used to control an alarm, valves, pump, etc. Available options include 4-20 milliamp output, 3 sensor input, 3 range capability and temperature. Internal electronic sensor substitutes are standard on all Monitor/controllers.

Sensors are available constructed in either 316 stainless steel or titanium. All sensors are provided with a 3/4″ MNPT polypropylene bushing and 10 ft./3 meters of cable. Optional PVDF or stainless steel bushings can be ordered, as well as longer cable lengths up to 100 ft./30 meters.

The following table briefly covers recommended Myron L meters for Dl water applications.

DEIONIZED WATER APP TABLE

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MyronLMeters.com is the premier internet retailer for all recommended Myron L meters above. Save 10% when you order online at MyronLMeters.com.

Categories : Application Advice, Case Studies & Application Stories, Product Updates, Science and Industry Updates, Technical Tips

Reverse Osmosis: MyronLMeters.com

Posted by 7 Apr, 2014

Tweet  Reverse Osmosis   RO Meter – RO-1: 0-1250 ppm with color band RO Meters The choice of professionals for years, this compact instrument has been designed specifically to demonstrate and test Point of Use (POU) reverse osmosis or distillation systems. By measuring electrical conductivity, it will quickly determine the parts per million/Total Dissolved Solids […]

 

Reverse Osmosis


 

RO Meter – RO-1: 0-1250 ppm with color band

RO Meters
The choice of professionals for years, this compact instrument has been designed specifically to demonstrate and test Point of Use (POU) reverse osmosis or distillation systems. By measuring electrical conductivity, it will quickly determine the parts per million/Total Dissolved Solids (ppm/TDS) of any drinking water.
With a single ‘before and after’ test, this handy device effectively demonstrates how your RO or distillation system eliminates harmful dissolved solids. It will also service test systems, including membrane evaluation programs.Save $25.00 on the Ro-1 this month with coupon code: ROSave25

 

Ultrameter II – 6PIIConductivity, TDS, Salinity, pH, ORP, Temp Pens

Reverse osmosis biofouling

Introduction
Water desalination via reverse osmosis (RO) technology provides a solution to the world’s water shortage problem. Until now, the production of fresh water from seawater has reached 21-million cubic meter per day all around the world (Wangnick, 2005). However, the success of RO technology is subject to improvement as the technology is challenged by a biofouling problem –a problem related to biological material development which forms a sticky layer on the membrane surface (Flemming, 1997; Baker and Dudley, 1998).
Continuous biofouling problems in RO lead to higher energy input requirement as an effect of increased biofilm resistance (Rf) and biofilm enhanced osmotic pressure (BEOP), lower quality of product water due to concentration polarization (CP) – increased concentration due to solutes accumulation on the membrane surface, (Herzberg and Elimelech, 2007), and thus significant increase in both operating and maintenance costs.

Recent studies and objectives
Recent studies show the importance of the operating conditions (e.g. flux and cross flow velocities) in RO biofouling. The presence of feed channel spacers has also been getting more attention as it may have adverse effects. A previous study (Chong et al., 2008) without feed channel spacers showed that RO biofouling was a flux driven process where higher flux increased fouling rate.

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Categories : Application Advice, Case Studies & Application Stories, Science and Industry Updates, Technical Tips

Testing Fountain Solutions: MyronLMeters.com

Posted by 6 Mar, 2014

TweetNeed to know the best meter for your application? Review our Bulletins which explain in clear detail the best model for your needs. If you have more questions, visit our FAQ section or send our Experts a question using the contact form. We’ll respond as quickly as possible! Visit MyronLMeters.com for videos, operations manuals, FAQ, […]

Need to know the best meter for your application? Review our Bulletins which explain in clear detail the best model for your needs. If you have more questions, visit our FAQ section or send our Experts a question using the contact form. We’ll respond as quickly as possible! Visit MyronLMeters.com for videos, operations manuals, FAQ, MSDS, and more information about Myron L meters.

Fountain Solutions
Accurate fountain (dampening) solution concentration control is essential for consistent, high-quality results in lithography. Low concentration can cause drying on the non-image area of the plate resulting in tinting, scumming, blanket piling, etc. High concentrations, on the other hand, bring about over-emulsification of the ink. This results in weakening of color strength and changes in ink rheology (body and flow properties). Correct concentration will allow the non-image areas of the plate to be appropriately wetted.

Ways to Test

Traditionally, pH was the test relied on to determine fountain solution concentration. Today, however, conductivity testing is recognized as a much more accurate method. Many modern dampening solutions are pH stabilized (or buffered), so only small changes in pH are seen even when dramatic changes occur in solution strength. Conductivity measurement is a fast and easy test which is more indicative of fountain solution concentration than pH. This is true for all neutral, alkaline, and many acid type solutions.

pH is still important, however, with unbuffered acid fountain solutions. Checking both conductivity and pH can provide valuable information. Acid fountain solution is a mixture of gum arabic, wetting agents, salts, acids, buffers, etc. Conductivity will tell you if the proper amount of most ingredients are present, but pH is necessary to check acid concentrations. pH will also determine how effective one ingredient, gum arabic, will be.

Conductivity Testing

What is conductivity? Conductivity is the measurement of a solution’s ability to conduct an electrical current. It is usually expressed in microsiemens (micromhos). Absolutely pure water is actually a poor electrical conductor. It is the substances dissolved in water which determine how conductive the solution will be. Therefore, conductivity is an excellent indicator of solution strength. To properly measure the conductivity of fountain solutions:

Test and write down the conductivity of the water used to prepare the solution.
Mix the fountain solution concentrate with the water, using the manufacturer’s recommendations or as experience dictates.
Measure the conductivity of the mixed solution.
Subtract the water conductivity value obtained in step 1. This is necessary because tap water quality can change from day to day.

The resulting number is an accurate indicator of fountain solution strength. Caution: because alcohol will lower a solution’s conductivity, always test solution conductivity before and after the addition of alcohol.

Determining the best concentration of fountain solution is mostly ‘trial and error.’ It can be very useful to make a graph, recording readings for every one-half or one ounce of concentrate added to a gallon of water. Record readings on a graph with the vertical axis representing conductivity values and the horizontal axis representing ounces/gallon. Such a graph will help ‘fine tune’ your system during future press runs.
For ‘on the spot’ fountain solution tests, Myron L meters are fast, accurate, and reliable. Measurements are made in seconds simply by pouring a small sample of solution into the instrument cell cup and pressing a button. Automatic temperature compensated accuracy and reliability have made our instruments popular in pressrooms worldwide.

pH Testing

Even though pH usually is not the best method to check the concentration of fountain solution, it is still very important and must be checked regularly. The pH of acid dampening solution affects sensitivity, plate-life, ink-drying, etc. Also, pH can change during a run if the paper has a high acid or alkaline content. pH, therefore, must be maintained at the proper level for good printing.

A convenient and accurate way to test pH (as well as temperature) is the waterproof ULTRAMETER II Model 6P or TECHPRO II TH1. The 6P has a 100 reading memory and the TH1 has a 20 reading memory to store test results onsite. The 6P also measures conductivity. All electrodes are contained in the cell cup for protection. Model M6/PH also measures pH and conductivity.

Continuous Control

For continuous monitoring and/or control of fountain solution concentration, we offer a complete series of in-line conductivity instruments. These economical, accurate, and reliable models use a remotely installed sensor and a panel/wall mount meter enclosure. Most contain an adjustable set point and heavy duty relay circuit which can be used to activate alarms, valves, feed pumps, etc. All models contain a 0-10VDC output for a chart recorder or PLC (SCADA) input, if required, (4-20mA output is also available).

The 750 Series II with dual set point option has become quite popular in pressrooms. The two set points allow a ‘safe zone’ for controlling fountain solution concentration.

Litho-Kit

Ultrameter II 6P, 512M5 and M6/PH are available with the useful LITHO-KIT. This accessory includes a foam-lined, rugged all-plastic carrying case with calibrating solutions and buffers. In addition, a syringe to simplify drawing samples and a thermometer for testing fountain solution temperature are also included.

 

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Categories : Case Studies & Application Stories

Horticulture Applications: MyronLMeters.com

Posted by 13 Nov, 2013

Tweet                    WHY ARE TESTS SO IMPORTANT? Modern growing practices include scientific evaluations of soil, water, fertilizers, diseases, etc. While some tests are best performed by a laboratory, others can be easily conducted on location, saving time and money. Three tests in particular, EC, pH, and ALKALINITY, […]

The Myron L Ag-6/pH

 

 

 

 

 

 

 

 

 

 

WHY ARE TESTS SO IMPORTANT?

Modern growing practices include scientific evaluations of soil, water, fertilizers, diseases, etc. While some tests are best performed by a laboratory, others can be easily conducted on location, saving time and money. Three tests in particular, EC, pH, and ALKALINITY, can reveal valuable information about water quality, soil salinity, and fertilizer concentration. Our portable AGRI-METERS™ provide you with a simple, fast, and accurate means of testing these parameters.

WHAT IS ELECTRICAL CONDUCTIVITY (EC)?

EC is the measurement of a solution’s ability to conduct an electrical current. For horticultural applications, the unit of measure is often expressed as millimhos. Absolutely pure water is actually a poor electrical conductor. It is the substances (or electrolytes) dissolved in the water which determine how conductive the solution will be.

Therefore, EC can be an excellent indicator of:

1. Water quality

2. Soil salinity

3. Fertilizer concentration

EC AND WATER QUALITY

The quality of irrigation water is one of the most critical factors influencing your growing operation. It is important to have a complete water analysis performed on a regular basis. Environmental conditions such as drought, changing seasons, heavy rainfall, etc., can cause the concentrations of dissolved salts in your water to vary significantly. These dissolved salts (i.e. calcium, sodium, etc.) can directly affect your plants’ health and, over time, render even the best soil useless.

You can monitor your overall water quality by testing its electrical conductivity with an AGRI-METER™. The higher the EC, the more salts are dissolved in your water. By comparing your EC with previous readings, you can tell if any dramatic changes have occurred. Nutrient deficiencies are possible when water is too pure (low EC) or if the relative concentrations of some nutrients are unbalanced (i.e. calcium/magnesium). On the other hand, nutrient toxicities or osmotic interferences can also be traced to water quality. Water EC of even one millimho or below can cause problems. High EC readings of more than two millimhos can suggest serious problems, and special cultural procedures may be required.

EC AND SOIL SALINITY

“Water, water, everywhere, but not a drop to drink” is an old saying that applies to your plants when the soil salinity becomes too high. Salts from irrigation water and fertilizers tend to accumulate in your soil or growing media. High soil salinity disrupts the normal osmotic balance in plant roots. In severe cases a plant will become dehydrated even when the soil is wet. Symptoms of high soil salinity include: leaf chlorosis and necrosis, leaf drop, root death, nutrient deficiency symptoms, and wilting. All too often these symptoms are not recognized as being caused by soluble salts in the growing media. Sampling your soil and testing the EC of an extract can reveal important information about a soil’s suitability and your crop’s health.

Samples should be representative of different depths and locations. An easy-to-perform extract method is available with a Soil Test Kit. A 2:1 or 5:1 water-to-soil ratio is made using the small vials provided. Soil test labs often use a method that calls for testing the EC of an extract from a thicker slurry. Therefore, you may see higher soil EC readings from a lab. It is important to standardize your sampling, extract, and testing methods. This will keep the difference between lab and field testing to a predictable factor.

EC AND FERTILIZER CONCENTRATION

You know how important fertilizer is to your plants, but do you know how accurate your fertilizer dosage is? Relying on traditional proportional methods is risky to plants and can waste expensive fertilizer. Improperly mixed fertilizer or a malfunctioning injector can lead to less than optimal results or even a disastrous loss of crops. Many fertilizer companies now recommend using a simple EC test to verify correct fertilizer concentrations. Many growers check their fertilizer injectors on a weekly basis, or they use a continuous EC monitor.

Fertilizer companies and suppliers often can provide a chart relating EC to parts per million concentrations of their various fertilizers. If one is not available for the fertilizer you use, carefully make some stock solutions at commonly used strengths and test their EC. This will give you a data base for future reference.

To test the EC of fertilizer solutions:

  1. Test and record the EC of the water to be mixed with the fertilizer.
  2. Test the conductivity of the fertilizer and water mixture.
  3. Subtract the water conductivity determined in #1 above.
  4. The resulting figure is an accurate indication of how much fertilizer is present (a higher conductivity means more fertilizer).

Important note: Interpretation of results differs from formula to formula and even among manufacturers of the same formula. Obtain the proper EC charts from the fertilizer company.

Myron L Meters sells both portable and inline instrumentation to make your fertilizer monitoring easy. Myron L AGRI-METERS™, AG-5 and AG6/PH, TH1, waterproof TECHPRO II™ models TP1, TPH1 and TH1, and waterproof ULTRAMETER II™ models 4P and 6PFCEare handheld instruments which make fertilizer testing as simple as filling a cup and pushing a button.

The Myron L 750 Series II™ EC Monitor/controllers can be used to continuously monitor your fertilizer concentration. Their “alarm” relay circuit acts as a safeguard in a fertilizer injection system or even as the main controller for your injector. A 0-10 VDC output for chart recorders or PLC (SCADA) input is standard on all monitor/controller models.

IMPORTANCE OF pH

pH, the measure of acidity or basicity, should be included in any soil or water test. It is well documented that growing media pH is critical to successful plant growth. This is especially true for new soilless mixes and hydroponics. pH affects the roots’ ability to absorb many plant nutrients. Examples include iron and manganese, which are insoluble at high pHs and toxic at low pHs. pH also directly affects the health of necessary micro-organisms in soil.

The effectiveness of pesticides and growth regulators can be severely limited by spray water pH that is either too low or too high.

ALKALINITY

It is important to note that testing the pH of irrigation water reveals only part of the story. Testing water alkalinity (bicarbonates and carbonates) is much more important than generally recognized. Alkalinity dictates how much influence the water’s pH will have on your soil and nutrient availability. In addition, alkalinity has a very great effect on the ease or difficulty of reducing the pH of water.

 

 

Categories : Application Advice, Case Studies & Application Stories