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.