External herbie overflow.. glass thickness?

[JDigital]

I'm looking to add an External herbie overflow box to my tank after some discussions with a few people regarding sumps (which I had originally planned on omitting from my build)

How thick does the glass need to be?

I have some left over glass that originally came with the tank for a glass top... but it is prolly only 5-6mm thick. Would this be thick enough or will I have to look else where for thicker glass? (and how thick?)

EDIT:
I'm looking at about 9" tall (half my tank height), 16-18" wide, and 6" deep.

Two 1 or 1.5" holes in the bottom for the drain lines. (haven't decided yet)

TIA
Josh

[fkshiu]

It really depends on the size of the external box with height being the most important consideration, I believe. On my Seastar tank the external Herbie box is 11"L x 6"W x 10.5"H and uses 3/8" glass.

[mark]

could you just use the length and width of the display then the height of the overflow in a on-line calculator for glass thickness?

[sphelps]

Both 5 or 6 mm will work just fine for the dimensions you stated. Be sure to use the right silicone, GE Door and Window 100% Silicone #1 works well.

For the holes you'll be fine with 1" drains for a herbie style, but use the bulkheads that require a 2-3/8" hole as you can get 1.25" Bulkheads that fit in the same size hole.

[JDigital]

Thanks sphelps. Just what I was looking for.

I called Speedy Glass this morning, and they mentioned 5-6mm glass and I didn't think that would be thick enough so they told me to call other places... Now I need to call back..

[sphelps]

If you're buying new you might as well use 6mm, it'll be easy to find and about the same price as the 5mm. Plus it's closer to 1/4" if you prefer to work with inches.