Great thing to do in FOWLR since you don't have to worry about stripping the water too clean of nutrients. It is no substitute for water changes. You will need a good skimmer - this is super important. Just use sugar - it is pure and cheap... you can mix it in water and dose MLs, or just use a measuring spoon to dose. You don't have to be all dead-on-balls-accurate scientific about it.
Go slow, watch your skimmer output and test your N and P. You should see the skimmer output get exponentially better and the N and P go down. The skimmate will likely stink a lot worse than before.
The only downside to this is if you add too much at once - the growing bacteria bloom with starve the fish of oxygen. Oxygen starvation is real - did I mention to go slow?