My 375 gallon is filtered with an eheim 2080 pro III (excess waste that isn't overflowed), reverse undergravel filtration utilising 4 powerheads (preventing some waste settling), and my main filter is my own diy design as follows; 75 gallon glass tank w/ 3 baffles, 1st, through a 3" filter pad with a carbon bag under it (yes, I use carbon... I like water to sparkle), through a section of pot scrubbers, onto a section of giant salvinia (veggie filter), then overflowed onto another filter pad and back into the display.
Eheim 2080 pro III @ 450gph
Eheim aquaball powerheads x 4 @ 172 gph
Eheim pump 1262 @ 900 gph