I have a 60 gal sump/fuge that is only partially filled with water. Is there a formula to figure out how much water I have in there? (Length x Width x square root of the pythagoreom theorom)? I knew I should of paid more attention in math class!

Multiply L x W x H in inches and divide by 231 to get your gallons. There's 231 cubic inches in 1 u.s. gallon. That's the way I've always done it.

FWIW and to impress folks a cubic foot is like 7.48 gallons. Call it 7.5 which is 3/4 of 10. so find some way of computing 3/4 of the cubic feet and add a 0. example: 4'x2'x2' tank 3/4 is 3x2x2= 12 add 0: 120 gallons. easy enough to get rough gallons in your head. perhaps not mine but yours yes. LOL my .02

wat about a bowfront tank? How do u add LR in ur math? I know my 20L isnt 20gal! ??? I deff should have paid more attention in math!

Just when I think I have folks all good and confused, Beaslbob shows up for a moment of clarity lol. Yup, clear as mud. Thanks for the responses, this helps.

wat about a bowfront tank? How do u add LR in ur math? I know my 20L isnt 20gal! ??? I deff should have paid more attention in math! I know what you're talking about. After my 125 with foam background was filled with lr and the 30ish gal sump both filled with water, I came up with a total water volume of 95 gallons!

Quote: Originally Posted by 1guyDude wat about a bowfront tank? How do u add LR in ur math? I know my 20L isnt 20gal! ??? I deff should have paid more attention in math! The way I would calculate a bow front is to multiply your length x height. Then for the width measure your side panel, then measure from the center of the bow to the back of the tank and split the difference. So if your side panel was 12" wide and the front of the bow measured 15" wide from front to back I would caculate my width as being 13.5" Make sense? To many veriables with rock to calculate accurately. Some rock is more porous and less dense then other rock. Best bet is just to keep track of what goes into the system when you first fill it.