i don't have a prefilter and i never have an ammonia or nitrate problem. I use lots of LR
and a clean up crew in the tank. THen i have the sump with a fuge and LR
rubble and skimmer. I do run a poly filter in the sump that i change out every month just to catch larger chuncks of debris and to keep everything in the fuge...in the fuge
...prefilter isn't needed.