I don't know to much about aquaclear but I know I have a penquin 170 that filters my 20g just fine, so I'd say you could probably go with an aquaclear mini and be just fine, but you can never have to much filtration either, expecially on a q/t tank, so if you have the money I'd go with the 150. Just that extra filtration would be nice, and gurantee good filtartion.