I live on well water and am trying to get my pH levels right so my fish will be well. The hot water from the faucet has a pH of 7.4 which is perfect for my fish. When ever I leave the water in a bowl on the counter for 40 minutes, the pH raises to an 8.4. The cold water comes out of the faucet at ph 8.4 while the hot at ph 7.4? Please help before my fish die.