SPS struggles

[Myka]

I don't think this will solve your troubles, but you could try using smaller amounts of carbon, and changing it out more often, like every 2-3 weeks. Your magnesium is a tad low too - should be 1350-1400 ppm.

Are there any maintenance things you do every 3 weeks or so since you're noticing the algae issues at that interval? Not necessarily immediately before the algae issue since it could take time for the corals to react.