rstiles:
A couple things:
Welcome to the Boards! This is a great place to be and ask questions.
Second . . . I warn you now . . . Beaslbob's methodologies have been repeatedly proven to be not only false, but detrimental to your system. I would strongly advise gathering all the facts you can before making a decision to follow his advise.
Now . . . about pH . . . I am unfamiliar with the osmo prep you mentioned, however I use RO water and have for wuite some time and never have used such a product.
Secondly, when you test at 2:00, how long have your lights been on at that point? pH is typically lowest at night and higher during the daytime hours as photosynthesis resumes in the light loving animals.
If it were me, at this point I would not add any buffers to anything. I would continue to change water with unbuffered RO water and IO salt as you are already doing. This way, you can determine one by one what exactly each additive does in your system.
To get the best measure of pH, measure when lights first come on, midway through the photoperiod, and right after lights out. Take the average of those numbers to get an good solid of idea exactly where you pH is and how far it flucuates.
Does this make sense?
