Hello everyone. I have a 45 gallon planted tank with two HOB filters. After two years of having a pH around 7-7.2 my pH has recently gone up to 7.8. A few months ago I added some mopani wood but I thought that this could cause the pH to decrease not increase. I also have added several more live plants but apart from that nothing has changed. Any ideas why my pH has increased like this? How can I get it down and keep it down? TIA Update: I think that everyone is correct. I went online and did some research and the same thing has happened to other people who use the all purpose Flourish. I read in several places that it can raise your pH eg. 7.4 to 8.0. I don't think I really need the fertilizer so I'll stop using it and see what happens. I'll update later. Thanks for your input everyone.