Personally, if you are a fan of Hang On Back filters, I'd look at the Aquaclear series from Fluval,
If it were me, I prefer Canisters and have the space under the tank for them, I'd look at a smaller Eheim or an Oase
If it were me, I prefer Canisters and have the space under the tank for them, I'd look at a smaller Eheim or an Oase