That's a 15 US gallon tank, right?
I'm sorry, I can't think in liters.

Actually, it's a 20 gallon tank, the l was for long.

snip20L tank (20"W X 12"D X 12.5"H) external dimensions/snip
Those are the dimensions for a standard 10 gal. I've got a 20 long and its
30 x 12 x13. Just wanted to help clear this up before things got weird.