I've posted in other areas on here...thought I had everything figured out enough that patience would get me in the desired range but that's not happening. In short, I have a 120 that I set up in the fall. Found and cured my own driftwood, bought some BDBG for substrate, filled the tank, tested parameters, added rosies...all was good. Until the woman in me decided I didn't like the driftwood pieces enough and started all over again. I removed the rosies to my daughter's tank and found and cured more driftwood. While visiting a LFS, I spotted a piece of holey rock and fell in love with it. I questioned the salesman if it would raise my PH a ton and he assured me it wouldn't. Right. Anyway, that piece of rock went into my fishless (thank God) tank back in November and sat that way ever since. A couple weeks ago, I decided to finally plant and stock the tank enough to cycle it again and tested the parameters. The GH and PH were so high that I concluded it had to be the rock and removed it...did a 30% PWC and retested the next day. PH was down from 7.9 to about 7.5 and GH had come down to 9 from 12. Not perfect but I decided to remove about 2 gallons a day and replace with 2 G of RO water to help reduce the hardness and PH gradually over time. But I've noticed that while the PH seems to be remaining stable, the hardness is climbign again. It was 10, then went to 11 and this morning, it was up to 12. I have tetras in my tank and I don't want to lose them. I'm thinking that the driftwood must have absorbed some of the minerals the holey rock leached into the water...and now that the water is less concentrated, everything the driftwood absorbed is leaching back into the water. Does this seem plausible? And if so, how long before the driftwood will no longer be leaching calcium carbonate and whatever else it absorbed back into my tank?