Algae needs a few things to grow...phosphates, nitrates and light. They really much more on phosphates compared to nitrates so if you can control your phosphate level, a small amount of nitrates in your water would'nt matter much.
You can try cutting down the photoperiod of your tank by a few hours and see if that slows down the growth of algae. If you have only fish and no corals...you might want to consider a tank blackout for 3 days.