Some quick questions:
Is this fish only (did not see any coral listed).
Do you use a sand bed (I'll assume you do, if not then I will shoot up some different questions)? How deep and how long has it been set-up/what are you cleaning regimes? Do you clean the sand or let it sit?
What kind of flow do you have in the tank?
How often do you due water changes and how much?
What do you feed your fish? How often? How much? If it is frozen do you thaw then strain out the water the frozen food was in (it is loaded with nutrients)?
P04 is a necessary test, but it is most likely going to not register (your algea is making sure of that) if it does then basically even with your algea there are not enough things in the tank to "bind" all of the phos inputs you add (ie: you need more filtration or less inputs).
Basically your inputs are exceeding the tanks capabilty to process the waste and the algea is stepping in to help out

. The extra waist is either in your sand, in your rocks, in the water you put into the tank (are you using ro/di or tap?) or the food you feed your fish. The waiste from the fish (poop etc) is not being processed fast enough to rid the algea of a nutrient source, is it growing on the rocks, on the sand or both? If it is on the sand and crawling up your rocks, then I would start cleaning the sand, if it is on you rocks and not sand, then I would turkey-baist the rock and start doing heavier waterchanges until it clears. The others can give you better info on mechanical filtration, all I use is a skimmer. A clean-up crew converts waist, it does not remove it. Unless you have a a means for removing clean-up crew waist then you are just converting poop/algea to poop, which in the end just feeds algea?
-John-