I think most people try to get a filter that turns over the water at least 5 times per hour, and 500 GPH would turn a 75g tank over about 6 2/3 times per hour (divide GPH by number of gallons). Probably would be fine. I try to get the largest filter I can without blowing the tank out of the water, and I usually run 2 filters per tank if it is over 40g.
What filter are you looking at? Different filters perform differently, so that GPH rule doesn't always work. I like canister filters like the Mag 350 or Marineland C-series. Eheims are very good but crazy expensive. Fluvals and Renas are pretty popular too, but I have never tried them. The only canister I've had is a Marineland C-360 (got in in Jan) for my 75g, and I run a back up Tetra Whisper HOB mainly for extra filter media to quick start my QT tank.
For HOBs, I know AquaClear filters are pretty highly recommended. In fact, PufferPunk has one that is 25 years old and has only replaced the impeller a couple times. Pretty impressive, huh? I really like my Emperor 280, but I'd go with the 400 model and get 2. But, I don't like to chance filtration with an underpowered filter.
I generally look at what the manufacturer recommends for my size tank and then get the next size up.
What filter are you looking at? Different filters perform differently, so that GPH rule doesn't always work. I like canister filters like the Mag 350 or Marineland C-series. Eheims are very good but crazy expensive. Fluvals and Renas are pretty popular too, but I have never tried them. The only canister I've had is a Marineland C-360 (got in in Jan) for my 75g, and I run a back up Tetra Whisper HOB mainly for extra filter media to quick start my QT tank.
For HOBs, I know AquaClear filters are pretty highly recommended. In fact, PufferPunk has one that is 25 years old and has only replaced the impeller a couple times. Pretty impressive, huh? I really like my Emperor 280, but I'd go with the 400 model and get 2. But, I don't like to chance filtration with an underpowered filter.
I generally look at what the manufacturer recommends for my size tank and then get the next size up.