I'd try to go bigger than a 10 gallon sump if you can...even a 15 gallon tank would be better if that's all you have for room (same footprint). You will only be able to have the sump 1/2 to 3/4 full to allow for backflow if your power goes out or you turn your pump off. If it's a very large tank, it won't work at all. The backflow will flood a 10 gallon sump. I wouldn't use a 10 gallon sump on anything larger than a 55, and even that is pushing it.