So I'm a little stumped: my Po4 has gone up a smidge (from 0.08ppm to about 0.1ppm). My sps are showing the change (lightening up in color a little). I'm also starting to see a little hair algae and lingbya (brown algae) too. But here's the weird part - my bio load has been cut by 60% or so. I used to have 7 fish and now I only have 3 (two clowns and a damsel) in a 55 gallon. I do a 6 gallon water change every two weeks religiously where I replace my carbon and add a chemi pure blue packet every other water change. Further, the chaeto in my refugium isn't growing like it was, but a ton of other algae is growing inside the refugium. Any ideas on why the rise in Po4 when nothing but a decrease in bio load has changed in quite some time? Is this due to an imbalance between nitrate and phosphate? If so how do I fix this?