It will be hard with that kind of bioload, but cut back the feeding and up the water changes. Only way to do it really. do you have any corals that you feed? If so stop that. You do not want to add anything that is organic to that tank cause it will break down into nitrates. Even if the fish/coral eat the food they poop it back out so it still stays in your tank.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.