hexagon tank how many gallons??

[sushi*roll]

There is a hexagon fish tank for sale in the paper for 90$, It includes everything (including gravel and stand). The person doesn't know how many gallons, so instead they said "about 4 feet tall" (im not sure if they mean the tank is 4 feet tall or tank and stand is)

What are the most common sizes for a hexagon tank??

Also they said it was used for a salt and freshwater. Does that mean the filtration system will be messed up and i'll have to buy a new one (im not sure what the tank was set up for last fresh/salt)

Any help would be appreciated.

 

[jellyfishwarland]

Here is a link that I found useful for this situation.
Aquarium Shapes and Sizes | Old Town Aquarium

 

[bassbonediva]

They must mean including the stand and/or hood...unless it's a custom-built tank. The biggest standard hex I could find was 60gal and it was still only 28"" tall (27"L X 18"D X 28"H).