So I plumbed my skimmer outside for fresh O2. I added Kalk to my ATO. Surface agitation is great. Problem is that Co2 builds up in my airtight home. I could never get it above 7.8 at the peak of the day. It would dip to 7.65 at night. I’ve finally got it to 8.05 with the window open next to the tank. I know, I know, most people don’t chase pH, but now it’s personal out of spite! Out of curiosity, I’d like to know how many of you get 8.1 or above without Kalk, skimmer plumbing, etc. Poll is open!