Building overflow question

[russ1976]

I am building an overflow for my yet to be born reef setup. I am using a 36? long tank. I may not be able to drill the bottom (tempered glass?), so am looking at drilling the back, or simply using siphons.

I have access to a laser where we cut polycarbonate for protective shields around testing devices. I can cut very small detail. I was looking at creating a crenelated top edge to the overflow to allow a little bit of variation in the tank level. How wide should I make the slots between the ?fingers?? I suppose too narrow and they would clog easily, but too wide and too many critters could be swept into the overflow.

Or, should I just cut a straight edge?

Thanks!

 

[georgelc86]

1/4" slots should be good.

 

[Imbarrie]

Measure one at your lfs

 

[autoponicz]

i have mine about 3/8th ...you want the water to be able to flow easily ...if not the water level will be higher than you expected....and you can use some gutterguard inside the overflow to prevent snails from clogging the plumbing...and make a top cover for it so fish and critters cant get into it...just a few ideas...so many ways to make an overflow