+ 1.panmanmatt said:That size sump will hold 25 gallons if ya fill it to the top. In all fairness I'd say you'll have about 13 or so gallons in there while it is running.
As for the right size sump, go for the largest size you can fit inside the stand. You can never really have too big of a sump.
NYCREEFER said:Panmanmatt what is the formula to figure out how much water a container holds?