Fill Water CH

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
When I added the R-0011L the water turned blue. Does that indicate CH is 0 or something else?
Correct - if not zero, then extremely low. If you expect that your CH level is very low, you can do the test so that each drop is 10, instead of 25, to get some extra precision. Use 25 ml of pool water, 20 drops of R-0010, 5 drops of R-0011L, and multiply the number of drops of R-0012 by 10 to get your CH level.

Also: "The sample may turn purple during the test, or go to blue for a moment and then turn back to red/pink. This is called a "fading endpoint" and is caused by interference from metal ions. If this happens, do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total."

Pool School - Calcium Hardness