So I'm trying to get serious about my tank game. I have a planted 5 gallon that I've had for about a year now and I'm taking readings on water parameters for the first time. What I found strange is that I measured the pH straight out of the tap and got a reading of 6.8/7.0. Normally I have water that I let sit for multiple days in plastic gallon milk jugs and after testing the tap water I tested the water in the jugs and found that the pH was 7.6 or possibly higher, since that's the highest result you can possibly get with my kit. I repeated the test on both sources multiple times and the answer held. Also i checked the water from my tank and it was also reading at the highest testable level. Any ideas why the discrepancy?