|The 55 US Gallon: shown are Dennison Barbs, Various Tiger Barbs, an Odessa Barb, and a variety of nice plants.|
Somehow, over the last month or so, my pH has crept up to 7.8, which is a change of about 1.3. Over a month, that much of a shift isn't that bad, but it did cause problems: I've lost all four of the original odessas, which were replaced on warranty; two of my tiger barbs, who seem to be fine now; and one of the S lineolata loaches that I love so much and can't replace.
I'm not particularly pleased. The culprit, as I have identified, is actually the "sand" I used. It's not a quartz sand, but a crushed stone which I have determined to include a large amount of carbonate minerals, thus making the water steadily more alkaline. It wasn't a problem before because my filtration over granulated peat did quite a bit to keep it in check.
Last month, however, I discontinued the use of the peat over sustainability concerns (I'm trying to reduce my hobby's overall environmental impact). Obviously, I'm going to have to re-continue it as soon as I can. In the meantime, it's nothing that can be done besides careful adjustment with vinegar and some careful attention to keep an eye on other problems.
There's been some other changes - the addition of a supplemental CO2 dosing system that helped keep the pH problem in check as well as promoting some rather aggressive plant development. However, a leak in the tubing I failed to detect means that the system is depleted, so I can't lean on that either.