[Ron Jeremy]

I'm setting up a 55g for 1 Rhom. Is an AC 300 and an ac mini enough filtration. The Rhom is ojnly 2"

 

[RhomZilla]

I say for a 55 gal, an AC500.. but for your size Rhom in the 55 gal.. AC 400. The 300 will be ok for now, but when your Rhom does get bigger(which wont happen anytime soon), you will need to get a bigger filter. So, you might as well be in the neutral zone.

 

[Raptor]

I'd get the AC500. Say in a or two you want to get a bigger tank. For a few dollars more at big al's you are set.