Another low PH thread.

[zum14]

So today I calibrated my apex prob to find my ph sitting at 7.66.... Hmmm.... So i did a search and came across the reefkeeping article written my randy holmes farley. I did some reading, did some tests. I took a cup of tank water and aerated for 15 mins. Tested with probe and ph test, found to remain the same at 7.6. I took a fresh glass of tank water and aerated again for 15 mins, but this time i put the air pump outside on my step. The ph tested at 7.91. I checked my kh at 6-7dkh depending on the test kit. Calciums at 430. Im thinking some of my problem is co2 in my house and the other problem is slightly low dkh. So do i start dosing to raise my alk and in turn bring co2 down and ph up or try an airstone with a fresh air intake to outside. Im not sure that aeration will totally fix the problem, it will bring co2 down and ph up but will that affect my alk? I know theres a lot of people using the hrv but thats not something i can take advantage of at this time. I never really watched ph much because people always say keep the big 3 in check and the rest will follow. Well in the article its saying 7.8 is the lower limit so i feel i need to do something. Thanks to anyone with any suggestions.