aquarium vernacular....

[fishgate]

When you say you have a "20 gallon sump" are you referring to how much volume is being taken up by actual water or the total capacity of the sump. I have a 20 gallon sump but will probably only put in 10 gallons of water. So do I have a 20 gallon or a 10 gallon sump?

 

[dlterry85]

usually it just refers to the size of the tank being used as a sump.

 

[E.intheC]

Most would say you have a 20 gallon sump