that is true, i want a 4 foot tank.. with 30 inches high i might be able to put more fish, but idk if my light could go all the way to the bottom. :/.. idk ill do some thinking.
just did a change over to a 150 (72x20x24) last weekend used 100lbs of new live sand along with the 100lbs+ of the rock from my old 90. I just tested water yesterday and everything is fine. I do need to get a cleanup crew.
Personally I upgraded to a 210 gallon over a year and if I did it again I would go with a 180 . Difference is about 5 inches. That extra depth is good but I am unable to reach the bottom for maintenance. It's a pain. I am always wanting to move a coral on sand bed or do something. Tongs are also awkward to deal with.