I have exhausted all possible methods that I am aware of. My powerheads are pointing towards the surface of the water. My outlet is half in and half out. My window stays open and I have an airpump outside with a line going into my built in sump (AIO) with that air being pumped in at it's highest capacity. I am at a loss here. My PH has not moved any higher than 8 and no lower than 7.8. I am shooting for 8.2 to 8.4. My PH was the same before opening a window and adding an airstone. It made no difference at all. Any help with this would be greatly appreciated.