[Sk8r]

I'm sure this thread will get moved to Reef Discussion: this forum is for questions to the mods.
But for your answer: do only 1 water change a week. Stop using chemicals. Run carbon to clean out the chemicals.
Give precise numbers for your parameters, like 8.3, 9.3, 1.025, or we're shooting in the dark.

But while we're mentioning dark, turn out the lights on your tank 3 days and shield it from daylight. If you have mh, turn on only actinic the 4th day. Do this once a month and be sure your skimmer is running at optimum.

This is not algae: it's bacteria that feeds on light, particularly a distorted sunlight spectrum that comes from window bounce light. It's called cyanobacteria. It's an extremophile, and survives most things, but it will die out in the dark.