Drilling for herbies

[ReefJunkie]

I want to drill two more holes in my 65 but I need some advice. The overflow is 8" x 6" with one hole and I want to make it dual herbie style. In my search I found the general rule of drilling at least a hole width apart. Think I can get away with another hole in my overflow area? Here's a pic
http://i100.photobucket.com/albums/m35/Seascaper/Picture069.jpg
I am also drilling a return at the top left.
http://i100.photobucket.com/albums/m35/Seascaper/Picture071.jpg

[mark]

When I've seen Herbies with an overflow, there's been two holes in the bottom of the overflow. For something you have without changing the overflow box, wondering if a just a bulkhead below the existing hole (for the primary drain), then a up turned 90° on the top hole for the secondary drain.

[mark]

db

[ReefJunkie]

good idea! Thanks Mark
As for return I haven't decided, just one on the left or two returns one either side...hmm

[mark]

since you getting the drill out anyways, 2 returns wouldn't hurt

[midgetwaiter]

When I've seen Herbies with an overflow, there's been two holes in the bottom of the overflow. For something you have without changing the overflow box, wondering if a just a bulkhead below the existing hole (for the primary drain), then a up turned 90° on the top hole for the secondary drain.

That should work. I have 2 holes side by side in the back glass with a box around them. One is restricted with valve and the other has a 90 on it so the backup is out of the water, works good.