68G cube becomes a 95G Reef :)

[Delphinus]

I've never tried it but I think if nothing else, that the worst case scenario you have to account for is that the lower T may need a pipe that goes all the way back up to the top to ensure water will never come splashing out of it. I suppose even if it did it would just empty into your sump so maybe it's not a big deal.

Sorry, I probably shouldn't reply to a thread when my answer really can be boiled down to "DUH, I actually don't know, DUH" but I thought I'd throw my two bits in.

Tank build looks great. Can't wait to see the results of your drain idea.. Why not just try it dry fit for now (yeah, the joins will leak a tiny bit but it would be enough to tell you if your idea is workable or not.. ??)