Anemone tank design challenge!

[a hill]

A 4' cube that is 36" tall sounds like a NIGHTMARE to me. I would have to get out the snorkel and mask to do anything in the tank.

I agree. Unless I can swim in the tank I think 18” of depth from substrate to surface is plenty.

24” tanks could run a deep sand bed to meet that requirement, but most don’t run those these days.

-Andrew