Need advice on how to build overflow

[TheDiscusKid]

Hi guys. I was planning on doing a drip system on one of my racks. The tanks are just 20H . I was wondering if anyone had any advice on building the overflows without drilling the tanks? I have seen it done, but the image on how it looked like slipped out of my head. Any advice would be great. Thanks

[simon.browm403]

try this site http://members.aol.com/krampetz/water.htm

and this http://www.cichlid-forum.com/article...er_changes.php