I say it takes much longer than a couple days, light out, to stop algea from growing- even with your nutrient export system under control. It can put a small dent in the algea, but it will come back.

How long has the rock been covered in algea? How long has it been in the system? There are ways to make algea covered, and nutrient packed rock good again, but takes time.

Looking forward to helping out! Sounds like you are already on the right track. Would like to see your tank algea free eventually. Lets hear more on the system, and go from there.