Healthy Water, Healthy People Testing Kit Support
FAQ’s for Healthy Water, Healthy People Classroom Drinking Water Testing Kit #6
- I’m not getting any results. How can I tell if this test is working correctly?
- If you have a HWHP 4 or 5 testing kit, they contain a special chemical packet called “TestYes™” which yields
a positive result for several parameters. Open a Test Yes packet and dissolve in 1 liter of distilled water. Use
this solution instead of the sample for your tests. You will get a result using this solution for alkalinity, chlorine,
copper, hardness, nitrate, and pH. You can also order “TestYes™” packets separately from Healthy Water, Healthy People
- After I added the phenolphthalein, the sample did not turn pink, what should I do?
This is common and will happen whenever the starting pH of the sample is less than 8.3. This means that there is no
phenolphthalein alkalinity in the sample. Continue with the test by adding the bromcresol-green methyl red indicator
and titrate to the endpoint for total alkalinity.
My sample turns light pink when I add the bromcresol-green methyl red indicator, not a blue-green color, what is wrong?
- If chlorine is in the sample, it will bleach the indicator. Start with a fresh sample and add one drop 0.1 N sodium thiosulfate per
100 mL sample to remove chlorine. Then begin the test as usual.
- How do I know whether to use the High Range or Low Range procedure?
- If you don’t know what the approximate alkalinity of your sample will be, use the high range procedure.
If your results are below 100 mg/L, you can increase your accuracy by repeating the test using a fresh sample
and the low range procedure.
- I am getting positive results and I’m sure there is no chlorine in my sample. Could there be an interference?
- Other oxidants such as ozone, bromine, and chlorine dioxide can interfere with the chlorine test. Keep the sample cube out of direct sunlight during the reaction time, because sunlight can react with the DPD indicator and cause a false positive result.
- What is the difference between free and total copper?
Copper can exist in water in several forms, such as cuprous (Cu1+) ions, cupric (Cu2+) ions, and complexed copper, in
which copper is bound with various chemicals such as EDTA. Free copper is defined as the copper ions that are
not complexed to EDTA or other strong complexing agents. Total copper includes free copper plus the complexed copper.
Copper occurs in natural waters, wastewaters, and industrial wastewaters in both free and complexed forms. Copper concentrations in drinking water are usually very low. Copper salts are often used to control algae, however they may also be toxic to fish and wildlife.
- My sample turns a purplish color and never turns blue no matter how much Hardness 3 titrant I add. What is wrong?
This is an indication that your sample contains an interfering metal. Repeat the test with a fresh sample, but add 1-2 drops of the Hardness 3 titrant first, then add the UniVer3, and then continue adding the drops of the Hardness 3 solution. The titrant may tie up the metals that interfere with the indicator and allow for a normal color change at the endpoint. Include the initial drops when determining the hardness concentration.
- After my sample turns blue, it keeps fading back to pink. What should I do?
If the sample contains high levels of calcium (>200 mg/L as CaCO3), calcium carbonate will precipitate due to carbonate in the UniVer3 reagent. The sample will turn blue but then slowly fade back to pink as the calcium carbonate slowly redissolves. Keep adding drops of the Hardness 3 solution until the sample remains blue. You can also start over and add several drops of the Hardness 3 titrant before adding the UniVer3. Include the initial drops when determining the hardness concentration.
- When I use the Test Yes packets, the solution turns orange after adding the UniVer3. What should I do?
The copper in the Test Yes solution combines with the UniVer3 reagent and causes this orange color, however this does not affect the test. Add the drops of Hardness 3 as usual until you see the color change.
- My sample turns a light pink-brown color after adding the UniVer3, why is this?
Iron and manganese in the sample can cause this color and interfere with the endpoint color. Repeat the test with a fresh sample, but add 1-2 drops of the Hardness 3 titrant first, then add the UniVer3, and then continue adding the drops of the Hardness 3 solution. Include the initial drops when determining the hardness concentration.
Total Bacteria/Total Coliforms
I do not have an incubator. Is there anything else I can use?
A constant temperature provides proper conditions for bacteria growth and suppresses growth of non-target bacteria. If the temperature is too high, the organisms may die. If the temperature is too low, the organisms may not grow well and non-target organisms may proliferate. An incubator that maintains a constant temperature is the best way to ensure correct results.
If you do not have an incubator, try placing the tester in a warm place such as on a hot water heater. The temperature should ideally stay at 95-99 degrees Fahrenheit during the incubation period.
How do I dispose of cadmium waste from the NitraVer reagents?
It is important to follow hazardous waste regulations for disposal of waste from this test. Federal regulations
may be superseded by state and local regulations, so it is important to check with a regulatory agency in your area
for disposal instructions. The Environmental Protection Agency maintains a hotline where you can find local regulatory
contact information; this hotline is 1-800-424-9346.