What to feed the tank?

[Frogger]

Your corals can do fine with low nutrients, mine were doing OK for a couple years. However if you want sps that aren't brown or dull you need some nitrates.

Not sure dosing nitrates is a can of worms, although it is a bit of work because you have to monitor it. It is actually very effective and your corals will start colouring up very quickly, I was seeing results within a week.

Adding fish, feeding more and reducing your skimmer time can all help but the results are not as quick.

I had problems with Acropower causing Cyano bacteria. According to Reef2Reef amino acids can be like candy to Cyano. You don't have to have high nitrates and phosphates to have a Cyano bloom, hair algae or dinoflagellates for that matter. Just ask Llorgon.