So I tested my PH the other day and wasn't sure to use high range or low range. So I did both. The low range came back with about 6.0, and the high range said it was 8.8+. I don't know which to believe. I could not find any information from my water supply company other that "PH ranges from 6 to 8".. thanks.. Which test should I believe? I'm going to do them both again now and see if I get different numbers since I just did a water change yesterday.