How long do you have your lights on per day? On an FO tank I would run them about 6 hours if your having problems with algae. Also, depending on the fish stock, I would encourage you to get some hermits, emerald crabs, and last but not least snails (I prefer astria and margarita) I run my lights for 6 hours starting at 3 pm. This way the fish get total dark from 9pm to 8am and a small amount of indirect sunlight during the day and then full light from 3-9pm (not sun). What about the water parameters and what do you have for circulation, i.e. powerheads, pump return, skimmer return etc.?