Quote Originally Posted by gordyjamz
I have a question. I have hth droptest kit from walmart. When I do the calcium hardness test, it asks to put 5 drops of hardness indicator in 25 ml of pool water. It says that it should turn red. mine turns yellow. what does that mean? is it too low? too high? does it really matter considering i have a vinyl liner AG pool?
Does it then turn blue when you add the drops of the re-agent?

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.