HI,
Have you checked for phos in your water, I had made the mistake of using some tapwater to replace some evap, and now when I take a water sample for testing it has amounts of phos . I ve read that most animals, plants , algae, will absorb it but will release it all when they die , example after a algae bloom die off ,this can cause another bloom. How much are you feeding your critters rinsing live food can remove a lot of that organic stuff example frozen shrimp,squid is pretty slimy..
I added a phos pillow that removes that and silica, incase any of that sand I bought at HD had silica.
Does your local fish store run all your testing for free. Thats a big plus.
Doug:sfish: