Sorry to post about this but it's really perplexing me. I set up my tank over 5 months ago and my pH has fluctuated from 7.4 to 8.2 over a week's time ever since. It is not a quick rise, rather gradual over 7-10 days. In the beginning, I had gravel and plastic plants. I now have black sand, a few real plants and 2 plastic plants. I also added mopani driftwood about a month ago. My water is moderately hard (18-19 drops de GH, KH is about 7 drops). When I sit my water out for 24 hours it rates 7.4. I can keep the pH stable at 7.4 by changing the water twice per week, but I just went camping and it's now back to 8.2 because I wasn't around to change it for 6 days. I'd just like to get a bit of control, if possible. Any thoughts? Edit : I've been cycled for a month, so it's not that.