Also Known As: Chemical Testing Kit
The right balance of chlorine kills algae, bacteria, and other organisms. However, too much chlorine can damage your pool surface, filtration system, bathing suits and skin.
To test chlorine:
1. Fill the small comparator tube with pool water to the 9 mL mark.
2. Add 5 drops R-0001 and 5 drops R-0002. Cap and shake to mix. If chlorine is present, the sample will turn magenta.
3. Match the resultant color with the colors on the comparator.* Record as parts per million (ppm) free chlorine (FC).
4. Add 5 drops R-0003. Cap and invert to mix.
5. Match color immediately. Record as ppm total chlorine (TC).
6. Subtract FC from TC. Record as ppm combined chlorine (CC). Formula: TC – FC = CC.
*If color is off-scale, repeat the test using half pool water and half tap water. Multiply the reading by 2 to find the approximate sanitizer level. If the color is still off-scale, repeat the test using 1.8 mL of pool water diluted to the 9 mL mark with tap water. Multiply reading by 5 to obtain approximate sanitizer level.
Free chlorine levels should be between 1.5 to 10 ppm for pools, 4 to 10 ppm for spas, and 3 to 10 ppm for wading pools. Combined chlorine should ideally be zero, but levels up to 0.2 ppm are allowed in most areas.
Water’s pH is the second-most important characteristic of healthy pool water. When pH is high, chlorine is less effective. Low pH can make the water uncomfortable for swimmers.
To test pH:
1. Fill the large comparator with pool water to the 44 mL mark.
2. Add 5 drops R-0004. Cap and shake to mix.
3. Match the resulting color with the colors on the comparator. Record as pH.
4. If pH is too high, add R-0005, drop by drop. After each drop, count, mix, and compare with color standards until desired pH is matched. See acid demand test treatment tables to continue.
5. If pH is too low, add R-0006, drop by drop. After each drop, count, mix, and compare with color standards until desired pH is matched. See base demand test treatment table to continue.
The pH of human tears, 7.5, is a good goal. Most municipalities allow pH levels between 7.2 and 7.8.
Alkalinity is an indicator of how easily pH can be changed. If alkalinity is too low, the pH has a tendency to bounce from the optimum 7.5 pH. If alkalinity is too high, pH can creep up.
To test total alkalinity:
1. Rinse and fill the large comparator tube with pool water to 25 mL mark.
2. Add 2 drops R-0007. Swirl to mix.
3. Add 5 drops R-0008. Swirl to mix. Sample should turn green.
4. Add R-0009, drop by drop. After each drop, count and swirl to mix until color changes from green to red.
5. Multiply drops in step 4 by 10. Record as parts per million (ppm) total alkalinity as calcium carbonate.
Alkalinity should be maintained between 80 and 120 ppm.
Calcium prevents water from pulling ions from pool plaster, grout or metal. However, if the water contains too much calcium, it will deposit on the pool surface and tile, and may cloud the water.
To test calcium hardness:
1. Rinse and fill large comparator tube with pool water to 25 mL mark.
2. Add 20 drops R-0010. Swirl to mix.
3. Add 5 drops R-0011L. Swirl to mix. If calcium hardness is present, sample will turn red.
4. Add R-0012, drop by drop. After each drop, count and swirl to mix until color changes from red to blue.
5. Multiply drops in Step 4 by 10. Record as parts per million (ppm) calcium hardness as calcium carbonate.
Calcium should be maintained between 150 and 400 ppm.
Cyanuric acid absorbs UV rays, which can lower chlorine levels. However, too much cyanuric acid will decrease the effectiveness of your free chlorine and can potentially increase combined chlorine levels.
To test for cyanuric acid:
1. Rinse and fill CYA dispensing bottle (#9191) with pool water to 7 mL mark.
2. Add R-0013 to 14 mL mark. Cap and mix for 30 seconds.
3. Slowly transfer cloudy solution to small comparator tube until black dot on bottom disappears when viewed from above.
4. Read tube at liquid level on back of comparator block. Record reading as parts per million (ppm) cyanuric acid.
Health department regulations do not typically require a minimum for cyanuric acid, but the maximum is usually set at 100 ppm. However, 85% of chlorine is preserved with a level of 20 ppm, so a recommended level is 30 to 50 ppm. Certain municipalities, including New York City, do not allow any cyanuric acid in pools.