It will work, but may take some fine-tuning. I have an overflow with 2 tubes in it. I had a problem with one of them losing siphon. I replaced one with a smaller diameter u-tube, and it works great, and never loses siphon. Another way I could have fixed the problem would have been to replace the pump with a stronger one, but I don't know if the overflow would be able to keep up with it. I've had the overflow for years, and don't know what it is rated at. The pump actually determines the speed it drains at, so if your overflow and pump work together, then adding another tube won't do anything. If you add another pump or replace your pump with a bigger one, you might need the extra tube. You might be able to add another bulkhead to the overflow box if you needed more flow also.
Sonny
[ November 13, 2001: Message edited by: Sonny ]
