So heres the latest...
I did the drip kalk thing for a few days. My original feeling that the pH issue was solved with adding kalk was kaput as soon as I couldnt add kalk as a dose, but instead had to drip... this caused my pH to return to 7.8.
So at that point I was totally stumped. I talked to a few guys at my LFS and they suggested pointing my powerheads up to the surface... but as I've mentioned here I really dont think it had anything to do with my aeration, but I was getting desperate and gave it a shot. To no avail.
Thats when I just gave up for a few days. I just could not understand what was going on. Everything was as it should be. I reread a few pH articles and I affixed peticular attention to the part about co2 causing pH to drop, and how adding kalk uses up availible co2, thereby raising pH in the process. I know from before adding kalk in a dose got my pH back to where it should be, so I began to wonder: was the pH rising because adding the kalk in large volume soaked up seriously over-abundant levels of co2? And if so, how did it get there?
I then decided that there just might be too much co2 in my home's air. The 1st go around of problem solving, I passed that option up because I thought my house was old enough to be not-air-tight to the point excess co2 couldnt possibly be the issue. But now I'm a desperate guy willing to try anything. So I gave it a shot. I opened the windows right next to the tank overnight.
AND WOULDN'T YOU KNOW IT. The next afternoon, after having the windows open for around 14 hours, I checked my pH and it was smack at 8.3. Unbelievable. In fact, I still dont fully believe it. I'm still monitoring everything to rule out any other possibilities, but after 3 days it seems to be the definite culprit.
1) Began with pH 7.8.
2) Next day, windows open 14 hours, pH 8.3
3) next night, room mate closed windows (didnt tell him what I was doing) Next morning, about 3 hours after lights on, pH 8.0
4) Reopen windows, few hours later pH 8.3
5) that night windows closed again (roommate has been informed at this point, now just being difficult) reopen windows... ph 8.2
6) today, windows open pH 8.3
The only thing is that it seems to fluxuate so quick, its hard to believe opening the windows is that effective, but like I said, thus far it seems to be.
Problem is, this is really only a temporary fix. The weather is pleasant right now and the window being open really doesnt affect the temp in the house, or the tank for that matter. When fall and ultimately winter rolls around, thats just not an option. So.... Im trying to ween the tank off the window right now, and instead see if house plants can take care of the co2 (i have the window cracked at the moment and 2 big green plants I just bought from Meijor's.) I'll check in the morning to see where we're at.