I did not know that. It's kind of silly when we have to calculate salt, sand, rock and livestock based on gallons.
But, as I said... so far the communication has been great. I am really looking forward to the new build.
I agree 110% it's definitely a silly way of doing things when we base virtually every decision from equipment to livestock based off our actual water volume. I feel that manufacturers think that because everyone adds sand and rocks anyway which can cut 10-20 gallons of volume off the total system anyway and that will vary from setup to setup, that going from outside dimensions is just easier.
Regardless, I hope you love your new tank either way! If you have the time, when you do receive the tank I would appreciate if you would throw a review of it in the thread below....
https://www.reef2reef.com/threads/your-thoughts-on-custom-tank-manufacturers.616102/