You could run the
canister filter with the current Biowheel 170 you have respectively giving you filtration fro upto 100Gal. If you are looking to get rid of that, the next size up filter would probably be best allowing you to add more fish in the future if you wanted with out having to worry about filtration.
$110 C-220 Rated up to 55Gal at
ValuePetSupplies.com. PetSmart is $30 more, and DrsFosterSmith is $50 more. I did not factor in any shipping.
$150 C-360 Rated up to 100Gal at
ValuePetSupplies.com. PetSmart is $40 more, and DrsFosterSmith is $50 more.
If you are looking at other brands too. Maybe this one will do the trick. It is $60 and rated up to 75Gal. I use this on our 46Gal tank. Odyssea CFS 4.
thefishfactoryonline.com