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pH
  • What is pH..?
    The concentration of hydrogen ions is commonly expressed in terms of the pH scale. Low pH corresponds to high hydrogen ion concentration and vice versa. A substance that when added to water increases the concentration of hydrogen ions (while lowering the pH) is called an acid. A substance that reduces the concentration of hydrogen ions (while raising the pH), is called a base.


  • What is a pH buffer..?
    Some substances enable solutions to resist pH changes when an acid or base is added. Such substances are called buffers. Buffers are very important in helping organisms maintain a relatively constant pH.


  • How does a Ph Monitor work..?
    A Ph Monitor is designed to give a continuous readout of the solution pH value. Milwaukee Instruments has 3 different types of pH monitors, and some have user set point alarms. You can find all our monitors under the applications heading.


  • How does a Ph Controller work..?
    A pH Controller is designed to give a continuous readout of the solution, and has a user set point which allows the controller to turn power on and off to an attached device. Milwaukee Instruments offers 2 controllers.


  • If I order a pH meter, what accessories do I need to use with it..?
    Your Milwaukee Instruments meter will come with everything you need to get started. You should consider ordering at least two pH buffers, one at pH 7 and the other at either pH 4 or 10, as well as storage solution to prolong the life of your probe.


  • Can I measure the pH of a gas..?
    The only way to measure the pH of a gas is to dissolve it into distilled water and measure the mixture. Technically, the pH of the distilled water/gas mixture will be that of the gas.


  • Is Automatic Temperature Compensation (ATC) really necessary..?
    The necessity of ATC depends upon the required accuracy of a pH reading, because pH readings vary with temperature. For example a sample with a pH of 7 at 25 degrees Celsius may have a pH of 7.08 at 5 degrees Celsius, and a pH of 6.98 at 60 degrees Celsius. Many of our units come with ATC.


  • Why does my SMS122 only come with 7.01 calibration solution..?
    Because the SMS122 is used primarily in an aquarium environment, with both fresh and salt water aquariums operation is in the pH neutral zone which is 5.5 to 8.5. We strongly recommend that your unit be calibrated at the pH 7.0 position only, so we have included a starter pack of pH calibration solution 7.01.


  • Why does my new pH probe have some type of salt around the cap..?
    Salt build up around the probe when it is new is from probe protective shipping solution, and it is normal to see crusting around the protective cap. Rinse the salt off and let the probe soak for an hour in 4.01 calibration solution, storage solution or bottled water, then follow the calibration procedure instructions.


  • How does one take soil pH measurements..?
    Use a soil to water ratio, of 2 parts soil and 1 part bottled drinking water. Pack soil in cup, and always use a flat bottom measuring cup to assure proper proportions, then add the water. Stir or shake the soil and water mixture vigorously, then let sit for 1 to 2 minutes. Turn on your pH meter and be sure you have calibrated your meter before running the test, remove the cap to expose the sensor, and dip the sensor completely in the solution. Move the probe in the mix to be assured of good water to probe contact, and record the reading displayed on the meter.


  • Why is a double junction electrode better than a single junction electrode..?
    A double junction electrode is less likely to become clogged because the second junction is located higher up in the probe out of contact with the fluid.


  • What pH calibration solution should I use..?
    All manufacturers of meters and testers recommend that you use their specific calibration solution. Most meter and tester manufacturers use high quality calibration solution mix and quality control for their own meters, so always use our 7.01 or 4.01 for your Milwaukee Unit.


  • Why is my pH reading jumping all over the place..?
    If you're using your pH controller or moniter in either an electrolytic or saline environment, such as aquatic or hydroponic uses, try removing your pH probe and place it into a cup of the same solution you're trying to measure. If the numbers stop jumping around, then its likely that you have stray voltage in your system that is being picked up by the pH probe. Once you have isolated the source of this voltage and corrected it, your readings should be fine.


  • What is the expected pH probe life..?
    All Milwaukee Instruments probes are warranted for six months, and should last from 18 to 24 months if the probe is clean and kept wet in the proper storage solution.


  • How do I test my pH probe to see if it needs replacing..?
    A simple test can be performed using Windex glass cleaner with ammonia, and any type of soft drink. The procedure is as follows; turn your meter or tester on and place the probe in a soft drink, which is acidic, and the reading will be from 2.7 to 3.9. Then go to the Windex with ammonia which is alkaline. Your display should move very quickly up the scale to a point above 10.0. If the probe slowly moves up the scale, then it is time to consider replacing it.


  • How do I clean my pH probe..?
    You should use MA9016 cleaning solution for cleaning your probe, and MA9015 for storage of the probe when not in use.


  • What is the difference between Single Point and Slope calibration..?
    Single point is almost always done at the 7.0 position. Single point is fine as long as the area you are testing is within the neutral zone of 5.5 to 8.5. However, for accuracy in most applications, you need to have two point calibration. That is why most Milwaukee Instruments come with a 2 point calibration procedure, and most of our units are provided with both 7.01 and 4.01 calibration solution.


  • How often should I do pH Calibration..?
    To be the most accurate, you should calibrate before each use or set of uses. However, most units will hold calibration very well. If you are using your unit everyday, then check it once each day. If you get a reading that is above or below what you were expecting, then check the calibration at that point and retest your solution. You can find a Calibration and Probe reference chart on the Tech Tips page of this web site.


  • How should I store my pH probe..?
    You should use MA9016 cleaning solution for cleaning your probe, and MA9015 for storage of the probe when not in use. All pH probes use a cloth junction in the construction of the probe. This cloth is part of the diagnostic process in reading the pH. Never let the probe dry out. If the cloth becomes dry, the unit will not be able to read.


  • Can I reuse my pH calibration solution..?
    No, evaporation and contamination quickly change the mix.


  • What are the symptoms of weak batteries..?
    For the end user to be assured that the readings are accurate and not worry about battery strength, all Milwaukee Instruments units are designed to shut down when the batteries become too weak to give an accurate reading.


  • During the calibration procedure, why does my PH52 or PH53 display keep blinking..?
    During calibration, the 7.01 display number will keep blinking but the pH icon in the upper right corner will stop. When the pH icon stops blinking, press set, and the display will roll to 4.01 and start blinking. Wait for the pH icon in the upper right corner to once again stop blinking, then press set and turn your unit off. You are now calibrated. If the pH icon will not stop blinking during the calibration procedure described, then you need to soak the probe for a longer period. Remember, the PH 52 and PH 53 are waterproof an,d take several hours to condition before calibration.




EC - Electrical Conductivity
  • What is EC..?
    EC Stands for Electrical Conductivity - which is the measurement of the ability of an aqueous solution to carry an electric current. It is measured with a small electrical current flowing between two probes set 1 centimeter apart. The EC as it is known, flows faster when a greater amount of salts are in the solution. Microprocessor technology scales the measurement of electro conductivity into either microSiemens or milliSiemens.


  • How do I store my EC probe..?
    Do not store your EC or TDS meter in any type of solution. After use of your EC or TDS unit, rinse the probe in either tap water or soapy water, to neutralize the acidic fluid that was tested.


  • What do I need to know about EC Calibration..?
    All manufacturers of EC meters and testers recommend that you use their specific calibration solution. Most meter and tester manufacturers use high quality calibration solution mix and quality control for their own meters, so always use the correct Milwaukee Instruments calibration solution for your specific unit. You can find the calibration chart in the Tech Tips page of this web site.


  • How do I do an EC conversion to TDS..?
    The math conversion chart is too involved to provide in a FAQ, so please go to the Tech Tips page of this web site.


  • How does temperature effect EC..?
    The optimum operational temperature is 77 degrees Fahrenheit. Little degrading of accuracy is seen between 55 degrees and 85 degrees. To assist you in getting the most accurate measurement, many of Milwaukee Instruments EC units have Temperature compensation built into them. When searching for specific models, look for the ATC designation.




TDS - Total Dissolved Solids
  • What is TDS..?
    TDS measures the ability of an aqueous solution to carry an electric current. It is measured with a small electrical current flowing between two probes set 1cm apart. The TDS as it is known, flows faster when a greater amount of salts are in the solution. Microprocessor technology scales the measurement of electro-conductivity into parts per million, or ppm.


  • How do I store my TDS probe..?
    Do not store your TDS meter in any type of solution. After use of your TDS unit, rinse the probe in either tap water or soapy water to neutralize the acidic fluid that was tested.


  • What do I need to know about TDS calibration..?
    All manufacturers of TDS meters and testers recommend that you use their specific calibration solution. Most meter and tester manufacturers use high quality calibration solution mix and quality control for their own meters, so always use the correct Milwaukee Instruments calibration solution for your specific unit. You can find the calibration chart in the Tech Tips page of this web site.


  • How do I do a TDS conversion to EC..?
    The math conversion chart is too involved to provide in a FAQ, so please go to the Tech Tips page of this web site.


  • How does temperature effect TDS..?
    The optimum operational temperature is 77 degrees Fahrenheit. Little degrading of accuracy is seen between 55 degrees and 85 degrees. To assist you in getting the most accurate measurement, many of Milwaukee Instruments TDS units have Temperature compensation built into them. When searching for specific models, look for the ATC designation.




ORP - Oxidation-Reduction Potential
  • What is ORP..?
    ORP stands for Oxidation Reduction Potential, or Redox. The word oxidation means to combine with oxygen. Oxidation involves an exchange of electrons between two atoms. The atom that loses an electron in the process is oxidized. The one that gains an electron is reduced. Chemicals like chlorine, bromine, and ozone are all oxidizers. They steal electrons from other substances, making them good water sanitizers.


  • How do I measure ORP..?
    An ORP probe is really a millivolt meter, measuring the voltage across a circuit formed by a reference electrode, constructed of silver wire in effect, the negative pole of the circuit, and a measuring electrode constructed of a platinum band, the positive pole, with the pool water in between.


  • What does an ORP Meter tell me..?
    For practical purposes, oxidizing agents are the good guys in the water sanitation picture, reducing agents are contaminants and are the bad guys. As we add oxidizer to water (Ozone or chlorine) the electrode generates a higher and higher positive voltage. As we add oxidizer to the water, it steals electrons from the surface of the platinum measuring electrode. I should point out that electrons are negative particles, and when we remove these negative particles, the electrode becomes more positively charged.


  • Why is my ORP reading jumping all over the place..?
    If you're using your ORP controller or moniter in either an electrolytic or saline environment, such as aquatic or hydroponic uses, try removing your ORP probe and place it into a cup of the same solution your trying to measure. If the numbers stop jumping around, then its likely that you have stray voltage in your system that is being picked up by the ORP probe. Once you have isolated the source of this voltage and corrected it, your readings should be fine.


  • My co-worker is using an ORP (Redox) electrode to measure the same solution as I, but our readings are not even close. Could there be something wrong with my electrode..?
    Because ORP or Redox is a relative measurement, it is almost impossible to compare two ORP electrodes directly. ORP electrodes come equipped with bands made up of platinum, gold, or hydrogen, and each band type will give you a different reading in the same solution. Instead, simply measure two solutions and note the difference between the two electrodes. Once again, the difference between two solutions should compare. Look for a change of state, rather than an absolute measurement.


  • How should I store my ORP probe..?
    You should use MA9016 cleaning solution for cleaning your probe, and MA9015 for storage of the probe when not in use.


  • Is there such a thing as ORP calibration solution..?
    Yes, you should first condition the probe using the Milwaukee Instruments MA9025 conditioning kit, and then you can check calibration with MA9020 calibration solution.


  • ORP reading comparison.
    You should be looking for a change of state, rather than an absolute measurement. ORP is a relative measurement, and it is almost impossible to compare two ORP electrodes directly. ORP electrodes come equipped with bands made up of platinum, gold, or hydrogen, and each type will give you a different reading in the same solution. Even if the electrodes are of the same band type, the leak rate through the reference junction will affect your readings. Instead, simply measure two solutions and note the difference between the two electrodes. The difference between the two solutions should compare.




DO - Dissolved Oxygen
  • What is DO..?
    Dissolved oxygen is one of many measures of water quality, but an important one for aquatic life. Like land animals, fish and shellfish require oxygen to survive. When oxygen levels fall below 5 mg/l, fish are stressed. At oxygen levels of 1 to 2 mg/l, fish die. The amount of oxygen that can dissolve in water depends on water temperature. Colder water can hold more oxygen than warmer water.


  • How does temperature affect my DO readings..?
    Temperature affects DO readings in two ways. First, it changes the permeability of the membrane. As the temperature increases so does the permeability of the membrane. As the temperature decreases the oxygen permeability through the membrane decreases. Secondly, temperature affects the amount of oxygen that can be dissolved in water. As temperature increases the oxygen saturation point of water decreases.


  • How does atmospheric pressure affect my DO readings..?
    Oxygen saturation of water is different at different pressures. Correction charts are provided in most instruction manuals. Many instruments automatically compensate for barometric pressure. The barometric pressure is either measured by the instrument or entered by the user.


  • How do I calibrate my DO Meter..?
    Use the Open Air calibration procedure provided in your unit instructions, or contact us at milwaukee@vol.com.


  • How often should I replace my membranes..?
    Recommended service time is 2 to 4 weeks, depending on the application and how often you are using the instrument.





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