or put some more live rock and chaeto in the "sump"
i've found from my HOB
refugium that Chaeto does a great job of collecting detritus and the copepods and what not that take refuge in it do a nice job of feeding on it.
i'm an advicate of natural filtration i am not one for chemicals, over time nature does what it has to do to keep life going. on a nano tank normal water changes and natural filtration will keep your system healthy. what do you think has kept my nano healthy for the 2 years i've had it and through the summer i neglected it more then i care to admit(was working away). my corals and fish are extremely happy and healthy