Hey guys
The formula to figure gallons of any tank is;
Length X Width X Height (in inches) then Divide by 231
I know this may be hard on a odd shaped tank with bumps and dents and stuff as is fits in and around stuff but it will give you a very good idea.
The more perfect the shape of the tank the more accurate the formula. Try it on a fish tank. (I used to build fish tanks as a hobby)
Hope it helps.
76 stepside 2wd
GMPP 350/350
basicly a big money pit, but a lot of fun.