figuring tank size

[msamsonz28]

When you measure your tanks, do you take into account the thickness of the glass? Considering that my tank is actually only 48g (according to the AA calculator) not the 55g I was told when I bought it. That's quite a difference!

 

[DeFeKt]

Just take it from inside dimensions like you have done already by the looks of it..
It's a way to make a cheap buck by shaving off a few mm of glass.