Well my wife shut the house up last night and turned on the a/c. No biggie till i look at my tank this morning and my ph was at 7.8. I opened the windows in the room the tank is in and it has been steadily climbing all day. It is at 8.0 now. I also just set up my auto top-off yesterday and got all my little leaks taken care of. I have it all filled up now with kalkwasser so i should'nt have that problem again. It is amazing the effect of CO2 build up in a small room can have on a tank.