Speaking of not remembering, I don't remember what causes betta's fins to curl. I thought I read that poor water quality can do it, but I don't remember what water quality parameters can do it. Or does infection cause it? Or do halfmoon betta fins curl naturally, and I'm just being a worrywart? He's only 5 months old, so he's still growing. They've been curling for the past few weeks. I keep close tabs on water parameters, and I make sure he always has 0 nitrates, nitrite and ammonia. I modified the Spec III filter to have a much bigger chamber for Matrix, a chamber for Chemipure, and some of the Spec stock sponge for mechanical filtration. When I added plants, I started having trouble with pH dropping too low. Last week, it kept dropping to 6.0. And I started having big algae blooms (I run the Fluval CF13 for 11 hours a day). So I replaced the Chemipure with Polyfilter to control phospates to curb the hair algae (it will also control dissolved organics, ammonia, nitrite, nitrates and many other things), dumped half the plants and one shrimp to reduce organic load and the effect of photosynthesis on pH. His water is always crystal clear and beautiful. And 79*F. The dips in pH and fin curling seemed to coincide. When I started medicating him 2 days ago, I removed the polyfilter. Of course, the hair algae is really happy about that. The fin curling is still happening, even though the pH has smoothed out in the past couple days after removing some plants and a shrimp. Any ideas what could be causing it?