i got 4 of those and up to top line with mine is twelve to 14 gallons so that is what i use for draining my 10 percent and filling 10 percent on water changes for my 125 gallon, plus worked great for my tank transfer from 75 gallon to 125 last year. I put live rock in one bucket and rock with corals and coral in another, inverts and fish in another. I got mine from dollar general.