What is the best brand of filter?

You can always go with German Blue Rams or Bolivian Rams or a pair of angels if you want cichlids in a tank that small. About the only mbuna you could do would be the elec yellow labs (or blues) and you would be limited to a pair. For a power filter AquarClear has plenty of repair parts available and is very versatile. The highest Iwould go would be AC70 and that would give you 300gph for a 10x turnover. Any Mbuna requires good water quality.
 
An AC 70 is my recommendation. And chose something besides mbuna.
 
I realy like the penguin biowheel filters myself. They seen to provide better filtration with the xtra bacteria in the biowheel:)
 
:) Most of the folks I know who keep Mbunas tend to stock heavy to minimize aggression. With that in mind I would choose the A/C 110 & as soon as you can upgrade to 55g. "T"
 
You should get a filter that is capable of filtering more than what your tank actually is. I have had an AC 200 on my 20 gal for 15 years and never once had any problems with it. I also have a emperor 400 running as a 2nd filter on my 125 gal. Again, I have had that filter for at least 10 years and never once had any problems with it. Both of these filters are still running after all of these years.

The only filter that I have used and would not recommend is the Fluval canisters. Piece of crap if you ask me. I have had that filter for 8 or 9 years and have had nothing but trouble with it. I am currently searching for a new one.
 
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