Rear Bulkhead Overflows?

[planethopper]

I'm having a tank built next year, and would prefer to not have overflow boxes inside the tank. I've seen a few options for this. At a LFS, I saw a tank drilled with several rear bulkheads a couple of inches below the water surface with basket-covered intakes to return to the sump. Are there any disadvantages to doing it this way? Would I be better off with outside mounted overflow boxes? All opinions welcome.

Thanks.

[m8298]

I've done this before. What I did, because I am paranoid, is figured out what size bulkhead I need for the flow of my pump, and I used two of them. My logic being, if one somehow plugged up while I wasn't home, the other would still handle the flow.

You obviously need to keep the basket covers clean at all times. But it does work. I put a third in as the return.

[George]

I have a setup with a single side-drilled pipe to feed the sump. I use an upturned PVC elbow with a screen insert to get an actual surface skim.

The upside is that you regain all the area taken up by a traditional in-tank overflow box. The downside is that you loose a certain amount of surface skimming effect (from what I've observed vs. my old setup with an overflow box) plus you have a greater potential for clogging/fouling, especially if you get an algae problem.