I am in the beginning stages of setting up my tank. I have a kent marine bio rocker however my tank is not drilled. So i bought a siphon box that hangs on the back so i am wondering will this leave to big of a whole that the octopus will be able to clime out of? i am getting a bimac if that makes a difference or not. The space would be about the same size of a Marine Land Emperor 400.