Sanity check please

[waterbear]

I have had similar problems with the aquachem hardness test (pretty much the same results of it working in tap water but not in pool water). I find it works better if I put in 10 drops of the hardness indicator. It then gives me results very similar to the Taylor test for CH. The better hardness tests such as Ben's and Taylors use 3 reagents. The first one is to help remove the interference from the magnesium in the water by precipitating it out as magnesium hydroxide. The HTH and Aquachem don't. Perhaps this is the problem.

[vanhout]

I had the same problem just yesterday. HTH kit wasn't working, but Ben's was. I'm at 12 FC right now, I figured it was related to that