Does it then turn blue when you add the drops of the re-agent?Originally Posted by gordyjamz
I don't trust my memory on this, but I THINK it means there's something like copper or iron in your water as well--but that the test is still valid. With a vinyl pool any calcium setting from 0 to 500 is OK. Essentially, you don't have to worry about it. I check calcium 2 or 3 times a season, just to be sure.
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