Refugium with chaeto or bio-pellet reactor

[davej]

Algae wasn't an issue but zoa's were clamping up and unhappy.
I was afraid that high phosphate was causing this. That was why I went down the road of reducing my phosphate levels. I never had a spec of visible green algae for a year. It was only after I lowered the levels to 0.04 levels that I had an outbreak of algae. I also added some new cuc to help out.

[reefmandan]

Something to consider as well is that certain algaes thrive under specific N:P ratios, and so if bringing the PO4 down brought that ratio to within an appropriate range for a certain algae, it has the potential to thrive.