Tank calculations?

[mr_alberta]

To calculate tank volume, do (LxWxH)/231. That should give you the approximate gallons the tank is.

Also, when using an old tank, you need to make sure the silicone is still in good shape. Its shouldn't be dry or cracked or anything like that. It should still be squishy. If the silicone shows any signs of weakening, you'll have to cut out all the old stuff, clean the glass at the bond points and resilicone the tank.

If you are unsure whether or not your silicone is still "okay," fill it up outside and let it sit for a while and check the seams to make sure there are no signs of stress on them.