I haven't done anything new to the tank, been set up and cycled for a couple of months. The ph from my tap is right at 7 and I just tested the tank to move some fish and I get a reading of around 7.4 +/-. Anyone know what causes that? (p.s. I've tested the tap after letting it sit overnight and still get a reading of 7). I tried a search, but it was too common....