How many holes is too many?
 

Well, before I hack away at the glass in my tank like a blind woodsman, I want to make sure that this is feasable:

http://members.shaw.ca/harvwong/untitled.JPG

The glass is, I believe, either 1/2" or 5/8" thick and is 45"x30". I want to cut a slot out (I was thinking 16"x1 1/2"?) and use an external overflow. Is this too many holes in the back glass? I may add another larger hole as a closed loop intake (or make the overflow slot bigger so I can put the closed loop intake in the overflow box). The faint gray line is the potential overflow box.

The reason for the external overflow box is space. Since the tank is only 19" deep, I wanted to maximize the space useable in my tank.

Now, this many holes won't structurally weaken the glass to the point of having a possible blow out or anything will it? Thanks for any suggestions.

i've been trying to look for a pic of the oceansmotion's guys tank setup, he's got like 12 holes drilled in his tank at random places..it's quite the furious looking setup...i'll keep looking for the pic.

How are you cutting out the slot for the overflow?

I was thinking to drill a small hole to start, then using the tile cutting rotozip bit I have.

Basically, do what this guy did on Reef Central:

http://www.reefcentral.com/forums/sh...le+and+cutting

Hey, you try it first Jim and tell me how it goes :mrgreen:

that should be fine just keep your holes about 2" from any edge at the closest. personaly I would drill them large enuf to accept larger bulkheads.. you can always reduce the size of piping with bushings but you can't go larger.

Steve

Excellent! Thanks for the replies thus far. One last question, would that overflow slot at 16" long x 1 1/2" wide allow enough water to flow through at a given point to have my closed loop inlet in the external overflow box? The pump would be either an Ampmaster 2700 or Sequence Dart.

If not, how big would the slot have to be? Anyone have a formula on how to calculate flowrates for things like this?

I think RC has a overflow calculator, not sure how accurate it is though.

http://www.reefcentral.com/calc/drain.php

-Richer

I have a bunch of glass out in the garage you could use as test pieces before you tackle your tank.Stop by on a weekend and we can setup a "test" piece.

Thanks for the offer Jim! I was actually going to try it out on this old cracked 10G sitting in my parent's garage.