I hate to jump in on someone else's thread, but I am having the same issue. My tank is fairly new, about 2 months old, and recently (this week) my PH started constantly rising. When I first got the tank running, my PH was around 8.0-8.2. It's at a point now, that when my lights are on during the day, the PH climbs to 8.6. I am using my Apex probe, which was just calibrated a few weeks ago. I also verified with another test kit, so it isn't the probe calibration. I do 2-part dosing and try to keep my numbers at alk-8, calcium-450, mag-1350. I've had to dose to keep alk and mag up, but calcium has pretty much stayed at 450 without dosing. I am pretty much stumped on what to do. I've tried aeration, but that seems to raise the PH even higher! Please help before things start dying
