Water Testing Instructions - Further Reading

Water Testing Instructions

For kits using Taylor reagents, e.g. K-2006 or TF100, based on posts to TroubleFreePool.com.[1]

You will find more extensive water testing directions at the Extended Test Kit Directions Archives.

More on recommended Pool Test Kits.

General Info

  • CC = Combined Chlorine, the been-used stuff.
  • FC = Free Chlorine, available for sanitation.
  • TC = Total Chlorine, TC = FC + CC.
  • TA = Total Alkalinity, dissolved alkalines.
  • CH = Calcium Hardness, dissolved calcium.
  • CYA = Cyanuric Acid, stabilizer for chlorine.
  • Swirl = circular motion like stirring with a spoon.
  • Take samples 12-18" below surface (elbow deep).
  • Rinse mixing containers before and after testing.
  • Drop size matters on chemicals that you count the drops and multiply for a result. Keep the bottle vertical, do not squeeze the bottle. Droplets should form and fall of the end of the tip once every second or so.

How To Take A Pool or Spa Water Sample

How To Take A Pool or Spa Water Sample

Are Dilutions Necessary When Testing A Pool or Spa?

Are Dilutions Necessary When Testing A Pool or Spa?.

Best Practices When Testing Water

Best Practices When Testing Water

Common Water Testing Errors

Common Water Testing Errors

OTO TC/pH Test (for K-1000 Test Kit)

This is the simple TC/pH "daily" test. The OTO chlorine test cannot be diluted to get a wider range; if TC shows > 5, use the FAS/DPD test to get a true reading.

  1. Rinse and fill test-block cells to indicated marks (doesn't have to be perfect).
  2. 5 drops R-0600 (yellow top) on the Chlorine side, 5 drops R-0014 (red top) on the pH side.
  3. Cap and invert to mix.
  4. Put a white sheet 2-3" behind the color blocks to make reading easier. Natural indirect light works best (e.g. outside in the shade). Match solution colors to the color blocks. Record as TC and pH.

The K-2006 kit uses R-0004 instead of R-0014; it works the same except it uses a bigger sample.

TC > 10 may cause pH to read too high (this gets worse as TC gets higher). You can wait for the TC to come down to get an accurate pH or you can correct the chlorine interference by adding 1 drop of R-0007 to a 50 mL sample; then add that treated sample to the comparator.[2]

pH Test

Tips to Reading pH

  • When doing a color matching test - chlorine, bromine, pH - you should read it in natural daylight, not looking thorough he comparator into the sun
  • Have a bright white backdrop to view the color comparator against. Shine a LED flashlight on a white piece of paper, and hold the pH kit 6 inches or so above it. That makes it very obvious which of the boxes is the closest match.
  • Try using four drops instead of five to make it easier to read and it doesn't change the result.
  • Take a 3x5 index card and cut it so you can see one gradients at a time.

FAS/DPD Chlorine Test

More complicated, but gives a wider range, more precision, and also separately measures FC/CC.

  1. Rinse and fill sample tube to 10ml mark.
  2. Use teeny blue scooper (hold the flat end) to put one heaping scoop R-0870 powder into sample, swirl to mix. (OK if not all dissolves.) Sample should turn pink. If it "flashes" pink then the pink disappears, add more R-0870. If there's never a hint of pink at all, skip step 3; FC=0.
  3. Add R-0871 one drop at a time, swirling the sample continuously, 1-2 sec between drops. Stop when sample turns colorless. Multiply #drops by 0.5 to get FC. (If it turns pink again after a few seconds, don't worry about it.)
  4. Add 5 drops R-0003, swirl to mix. If it remains colorless, CC=0. If it turns pink, again add drops of R-0871 (swirling continuously) until it turns colorless. Multiply drops by 0.5 to get CC.
  5. CC > 0.5 indicates a need to follow the SLAM Process.

For extremely high FC levels, you can use 5ml sample water and 5ml chlorine-free water (e.g. distilled water); then each drop of R-0871 counts 1ppm FC/CC. This can save on test reagent.

How Much R-0870 Powder to Use?

The discussion of enough DPD powder in the FAS/DPD test seems interminable. It's been going on in this forum since 2007 and probably long before that.[3]

The simple answer (no overthinking required) is if the pool water sample turns pink or deep pink, you have enough powder. Done.

So, what if the solution Doesn't turn pink? Easy again.....you have no chlorine in your pool.

A seldom seen exception to the above is when you add the powder and the solution "flashes" pink but almost immediately turn back to clear. Now you know you have very high chlorine and will need to add another scoop so the solution stays pink, then conduct the test normally.

Very often, folks are inaccurate with this test when they fail to complete it properly. The dropper for the R-0871 solution must be held vertically, drops allowed to "fall" off the dropper tip, AND YOU CONTINUE TO ADD DROPS UNTIL THE LAST DROP RESULTS IN NO FURTHER COLOR CHANGE. Subtract that drop that made ABSOLUTELY no more change and the result is the end of the test.

Total Alkalinity Test

  1. Rinse and fill sample tube to 25ml mark.
  2. Add 2 drops R-0007; swirl to mix.
  3. Add 5 drops R-0008; swirl to mix. Solution should turn green or blue.
  4. Add R-0009 one drop at a time, swirling continuously, 1-2 sec between drops. Repeat until color changes, and stops changing.
  5. The last drop that caused a change is the drop count. Multiply #drops by 10 to get TA.

Calcium Hardness Test

Use quantities in [brackets] if CH is very high (>400) and you have trouble getting a clear transition to the blue endpoint.

  1. Rinse and fill sample tube to 25ml [10ml] mark.
  2. Add 20 drops [10 drops] R-0010; swirl to mix.
  3. Add 5 drops [3 drops] R-0011L; swirl to mix. Solution turns red to indicate calcium is present.
  4. Add R-0012 one drop at a time, swirl to mix after each drop. Repeat until color changes to blue (and stops changing).
  5. The last drop that caused a change is the drop count. Multiply #drops by 10 [25] to get CH.

Cyanuric Acid Test

For cold water (<70F), let sample warm up first.

For CYA anticipated <90ppm:

  1. Put sample in mixing bottle (up to the mark, ~ halfway).
  2. Add an equal amount of R-0013.
  3. Shake about 30 sec; let stand 2-3 minutes; briefly shake again.
  4. Glance into C.A VIEW TUBE, slowly pour mixture in until the black dot is not seen when you glance in. Do not look for the dot. Natural indirect light gives the best readings.
  5. Gradation closest to the fill level is CYA.

After reading, pour mixture back into the mixing bottle and try step 4 again; repeated readings on the same sample will lend confidence in the result.

CYA > 90 dilution Test

For CYA > 90ppm, repeat the test adjusting the procedure as follows:

  1. Fill the mixing bottle to the lower mark with pool water.
  2. Continue filling the mixing bottle to the upper mark with tap water.
  3. Shake briefly to mix.
  4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
  5. Continue the test normally from adding R-0013, but multiply the final result by two.

If you need to dilute the pool water further then apply these ratios:[4]

Pool water Tap or distilled water Multiply result by
1 1 2
1 2 3
1 4 5

Note that when doing a diluted test not only do you multiply the range of the test you multiply the error rate of the test, so results are a ballpark - not an absolute.

See CYA Testing for tips in how to read the test results.

Wait Times Between Chemical Additions

Chemicals can be safely added to the pool 10 minutes apart from each other with the pump running for good circulation.

Exception – Pools that recently increased Calcium Hardness (i.e. added Calcium Chloride) should wait at least 24 hours before trying to increase pH or TA by adding Bleach, Borax, Soda Ash, Baking Soda. Doing so can put the pool at risk of clouding the water by precipitating Calcium.