Archive for December, 2010
TweetWater quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of the application. It is most frequently used by reference to a set of standards against which compliance can be assessed. The most common standards used to assess water quality relate [...]
Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of the application. It is most frequently used by reference to a set of standards against which compliance can be assessed. The most common standards used to assess water quality relate to drinking water, safety of human contact and for the health of ecosystems.
Water quality is a very complex subject, in part because water is a complex medium intrinsically tied to the ecology of the Earth. Industrial pollution is a major cause of water pollution, as well as runoff from agricultural areas, urban stormwater runoff and discharge of treated and untreated sewage (especially in developing countries).
The complexity of water quality as a subject is reflected in the many types of measurements of water quality indicators. The list below represents some of the simple measurements that can be made on-site in direct contact with the water source in question:
- Total Dissolved Solids (TDS)
- Oxidation Reduction Potential (ORP)
- Dissolved oxygen
More complex measurements that must be made in a lab setting require a water sample to be collected, preserved, and analyzed at another location. Making these complex measurements can be expensive. Because direct measurements of water quality can be expensive, ongoing monitoring programs are typically conducted by government agencies. However, there are local volunteer programs and resources available for some general assessment. Tools available to the general public can be found here.
TweetMeasuring the pH of pure DI water is easy when you know what to expect. In theory, pure water should have a pH of 7. When you actually measure the pH, it will most likely fall between 5.5 and 7 due to its absorption of CO2 from the atmosphere. This natural occurrence forms carbonic acid [...]
Measuring the pH of pure DI water is easy when you know what to expect. In theory, pure water should have a pH of 7. When you actually measure the pH, it will most likely fall between 5.5 and 7 due to its absorption of CO2 from the atmosphere. This natural occurrence forms carbonic acid in the water, lowering the pH. Since DI water is pure, there is nothing to buffer it and stabilize the pH. Below are a few tips to increase the accuracy of your pH measurements.
Tips for accurate pH readings
- First and foremost, use a high quality ph meter and ensure that it is properly calibrated with pH buffer solution. Check the manufacturer’s recommendations for calibration. The Ultrameter II 6P and the Techpro II TPH1 are portable pH meters that are extremely accurate and easy to use.
- When using a portable pH meter, avoid cross-contamination by thoroughly rinsing with the DI water that you will be sampling. If a glass beaker or cup is to be used, rinse that as well.
- Use small samples and minimize exposure to air, as this will lower the pH value. Taking samples from an open-air drum or tank will typically give erroneous readings. Collect samples from a sample port if possible.
- If you have access to high-purity reagent grade KCl (Potassium Chloride) salts, then you can buffer the DI water to stabilize the pH. Adding a tiny amount to the pure DI water sample will increase the ionic strength and reduce the absorption of CO2 from the atmosphere. Be careful not to contaminate the KCl salts. Use proper tools/utensils to add the KCl salts
- If no salt is available and all you need is a quick check of your system, you can flow the water from a sample port into your portable pH meter to measure the pH values. This will take slightly longer to stabilize. Be sure to use an accurate, waterproof pH meter and hold it closely to the sample port.
- Changes in temperature can affect the pH. Use a pH meter that is temperature compensated to remedy this issue.
If you need pH buffer solution, you can find it here at an affordable price.
TweetThe need for proper dialysis water quality tests Kidney failure is a big problem in the U.S. and it is only growing. More than 350,000 Americans receive dialysis treatment through private clinics, independent centers, and hospitals, while 8% of U.S. dialysis patients treat themselves at home. As more and more Americans develop a need for [...]
The need for proper dialysis water quality tests
Kidney failure is a big problem in the U.S. and it is only growing. More than 350,000 Americans receive dialysis treatment through private clinics, independent centers, and hospitals, while 8% of U.S. dialysis patients treat themselves at home.
As more and more Americans develop a need for dialysis treatment, water quality instrumentation manufacturers are looking for a way to help clinics improve their quality standards and efficiency.
Part of the problem
If you are constantly recalibrating your instruments, performing a decontamination process, or sending the meter in for repair, then you’re wasting time. As the number of dialysis patients increases, delays in the water quality testing add up. Today, you have options when it comes to testing dialysis water quality and dialysate composition.
Some instruments require annual calibration or an inconvenient decontamination process after each use. Using an instrument that requires direct contact with fluid means you have to decontaminate the meter before helping the next patient. If done incorrectly, the water treatment system and distribution piping can become contaminated, putting lives at risk.
More downtime occurs when dialysis meters have to be sent back to the manufacturer for annual calibration. If you are a clinician or biomedical equipment technician at a dialysis clinic, then you know how frustrating it is to work with problem instruments.
Make your job easier with the Digital Dialysate Meter™ D-6
MyronLMeters.com features the new Myron L Digital Dialysate Meter™ D-6.
Unlike other instruments, this meter does NOT have issues with holding calibration or giving consistently accurate readings. It does NOT have an inconvenient decontamination process or require any annual factory calibration. The meter does NOT use paper strips or reagents that expire or allow for subjective interpretation of results.
The D-6 simplifies testing in a variety of clinical applications: dialysate testing, water quality control, system disinfection, equipment calibration and effluent monitoring.
The D-6 tests both acetate and bicarbonate dialysate quality. It measures conductivity, pH and temperature to ensure proper mixing during dialysate preparation and as a final check of dialysate quality before hemodialysis treatment.
Order a bluDock™ Bluetooth Wireless Communication Package and your meter can communicate wirelessly with your computer to download your saved measurements. Say goodbye to clipboards, data entry, and human error.
Make your job easier now, order online and SAVE 10%.
Tweet If you are a greenhouse grower then you are most likely familiar with the importance of proper water quality for your crops. Water quality can easily be determined by taking measurements periodically. It is important to use accurate and reliable equipment to perform the measurements. A wide selection of high quality conductivity testers and [...]
If you are a greenhouse grower then you are most likely familiar with the importance of proper water quality for your crops. Water quality can easily be determined by taking measurements periodically. It is important to use accurate and reliable equipment to perform the measurements. A wide selection of high quality conductivity testers and hydroponic pH testers can be found here at an affordable price.
To determine the suitability of water for irrigation you can easily take measurements of the Electrical Conductivity (EC) and the Sodium Adsorption Ratio (SAR). In general, the higher the EC and SAR, the less suitable the water is for irrigation. Irrigation using water with high sodium adsorption ratio may require soil amendments to prevent long-term damage to the soil.
SAR measurements are provided with laboratory analysis of the water. However, EC measurements can be made using a portable EC meter. The Myron L AG6/pH was specifically designed as a pH and conductivity tester for greenhouse crops.
As a rule of thumb, the water is considered borderline and its use can present problems if conductivity values are higher than 0.8 millisiemens/cm (mS) and SAR is over 4. If the conductivity measurement is below 0.8 mS and the SAR measurement is below 4, the water is suitable for greenhouse irrigation. Particular management practices should be used when water is outside the acceptable limits. This might include using a growing medium with excellent drainage, leaching with every watering and compensating the sodium with calcium and magnesium.
If galvanized steel is used throughout the greenhouse and water is reclaimed for irrigation, it is a good idea to check the amount of Zinc in the water and make nutrient correction accordingly.
Many greenhouses use drip irrigation systems, which are efficient and low maintenance, but nozzles can become clogged by hard water. Check for high levels of bicarbonates (above 100 ppm) in the water and neutralize with the appropriate acids.
There are many factors that affect water quality and greenhouse crop growth. Consult your fertilizer manufacturer for recommendations on proper nutrient levels.
TweetThe TDS to Conductivity correlation is non-linear and no single multiplier can determine the relationship. Therefore, a simple conversion table has been established to help you determine an approximate conversion factor. Different types of salt have a different conductance value. The table below shows the three standard salts types. To simplify this conversion, Myron L [...]
The TDS to Conductivity correlation is non-linear and no single multiplier can determine the relationship. Therefore, a simple conversion table has been established to help you determine an approximate conversion factor.
Different types of salt have a different conductance value. The table below shows the three standard salts types. To simplify this conversion, Myron L has developed Conductivity/TDS meters that allow you to select the different salt types and does the conversion for you automatically. Take a look at the Ultrameter II 4P or the Techpro II TP1.
|Conductivity at 25 °C||TDS KCI||TDS NaCI||TDS 442|
|ppm Value||Factor||ppm Value||Factor||ppm Value||Factor|
TDS 442 – This solution best represents natural freshwater. The Myron L Company developed the 442 standard nearly 50 years ago. It is still the world’s most accepted standard.
TDS NACL – This sodium chloride solution best represents seawater, brackish water, or other high saline solution.
KCL TDS – This potassium chloride solution is a very stable salt and is an international calibration standard for conductivity measurements.
All of these different solution types are available here at an affordable price.
TweetWhat is the ORP of water? ORP stands for Oxidation Reduction Potential, also known as Redox. It is a measure of the tendency of a chemical species to acquire electrons and thereby be reduced. The ORP measurement is displayed in millivolts (mV) and the usual range for ORP meters is (+1000 mV) to (-1000 mV) [...]
What is the ORP of water?
ORP stands for Oxidation Reduction Potential, also known as Redox. It is a measure of the tendency of a chemical species to acquire electrons and thereby be reduced. The ORP measurement is displayed in millivolts (mV) and the usual range for ORP meters is (+1000 mV) to (-1000 mV) with no temperature compensation. It is not a direct measurement of concentration, but rather an indicator of the activity level or strength of an oxidizer or reducer.
An oxidizer gains electrons, while a reducer loses electrons. Examples of oxidizers are: chlorine, hydrogen peroxide, bromine, ozone, and chlorine dioxide. Examples of reducers are sodium sulfite, sodium bisulfate and hydrogen sulfide. Like acidity and alkalinity, the increase of one is at the expense of the other.
When measuring with an ORP meter, a positive voltage shows a solution gaining electrons (oxidizing) and a negative voltage shows a solution losing electrons (reducing). For instance, chlorinated water will show a positive ORP value and a solution with sodium sulfite will have a negative ORP value.
ORP meters are used for swimming pools and spas, drinking water, cooling tower disinfection, and groundwater remediation. ORP meters are also crucial for bleaching applications, cyanide destruction, chrome reductions, metal etching, fruit and vegetable disinfection and dechlorination.
Many organizations around the world have accepted ORP as a standard for disinfection. An ORP of 750 mV was adopted by the German Standards Agency in 1982 for public pools. The National Swimming Pool Institute also adopted an ORP of 650 mV for public spas. The World Health Organization (WHO) adopted an ORP of 700 mV as a standard for drinking water.
How to use ORP?
Oxidation Reduction Potential is a convenient measure of the oxidizer’s or reducer’s ability to perform a chemical task. It is a more consistent and reliable measurement than chlorine alone. You can establish an ORP measurement at which acceptable sanitation is achieved and maintained for your application by testing the rate of inactivation of various microorganisms. There are published standards for many applications or a lab water analysis should be able to provide these results if necessary. For example, the above paragraph mentions the 750 mV standard for public swimming pools. Once that has been determined you can use an ORP controller to maintain that level of sanitation.
Similar to pH, high purity solutions will take extra time to stabilize a reading due to the low ionic strength. Also, if the ORP measurement of a sample solution is similar to the mV of the ORP probe, it will take slightly longer for a reading to respond and stabilize. Rinsing the probe with a strong oxidizer will help to increase the reaction time and give accurate readings quickly. Ensure that there is not residual solution in the ORP probe by rinsing thoroughly with the solution to be tested.
ORP meters like the 728II are used to monitor the sanitizer level. A pH controller, such as the 723II, is also used to monitor pH. The controllers automatically turn the appropriate chemical feeders on and off, as required to maintain the proper sanitizer and pH levels. This results in good water quality and elimination of chloramines and other unpleasant contaminants, as well as in savings in chemical and labor.
Generally, ORP meters without pH control should not be used with alkaline sanitizers such as sodium hypochlorite or calcium hypochlorite. If the pH remains fairly constant, these inexpensive controllers provide a very cost effective solution to the problem of chemical control in small commercial applications.
Other handheld instruments like the POOLPRO PS6 have been designed to test ORP reliably for swimming pools and other applications. If you are in the medical dialysis industry, you will definitely be interested in the Digital Dialysate Meter D-6 that test ORP, among other parameters.