Carpet tank size

[EnFuego]

I'm thinking of setting up multiple tanks with one common sump. I want to set up one of the tanks specifically for a either a gigantea or haddoni. Would an 18" cube work? I've seen folks with carpets with tanks that are longer but only 18" wide, so it seems like it should work if I find a smaller anemone and limit feedings. The only inhabitants in the tank would be the anemone and a pair of clowns and maybe a handful of inverts. Two other tanks would be connected to a common sump with the anemone tank.

Thanks.

 

[Faye]

40b for haddoni or gig. They both get to be like 2 ft in length.