Definately lots of strength there :D

I think it would still be strong enough. Its a great idea, I wish I would have thought of that before I filled my tank. I definitely get less light penetration through that glass.

Just out of curiosity why not just do 2 - 4" cross braces
http://www.canreef.com/vbulletin/pic...&pictureid=896

Ideally the tank would be just eurobraced without any crossbracing at all, but this was a used tank that I picked up for dirt cheap and just modifying it to fit my needs in the easiest way possible. For me to rip out the exisiting brace and re-brace it would be a lot of work and time consuming and that nice black trim would probably be all broken by now (I'm still debating wether to keep the trim yet) This took me less than an hour total and I think I achieved decent results. I think it was just a matter of me taking the easiest route possible while achieving results that I would be satisfied with long term. It ends up being 2.5" too, so that's better than 4" I guess.

So yesterday afternoon, my kids helped me cut the glass for the overflow. I was quite pleased with the results. First, we semi cleaned up the glass to be cut (it was full of silicone and fish water residue). I got this 3/8" glass for trade for some other clean 1/4" glass that I had sitting around in the garage, so I'm not complaining. Here are pictures.

This one shows my 2 outside walls of the overflow and the divider. The kid's books was just used to prop the glass up will breaking it along the score line.
http://i600.photobucket.com/albums/t...g?t=1238251906

This picture is to show that I got pretty close to 90 degree cut. I was surprised that the newly cut edges were not sharp. I could run my hand up and down the fresh edge quite comfortably. Sorry for the fuzzy picture (cell phone camera)
http://i600.photobucket.com/albums/t...g?t=1238252008

And here my son being a goofball. He was helping me with the breaking of the glass. This picture shows the fresh cut :)

http://i600.photobucket.com/albums/t...g?t=1238252126

Hopefully today or tomorrow I can drill the drain holes and assemble the box. I have to get a wire brush or something to clean the excess silicone of the edges though. I'm not too much of a fan of this. At least we have a bit of progress.

Excellent job on cutting the glass. Your son sure is a little cutie.

Thank you...it's been a few years since I've cut glass. It's easire with a helper now :). Hes really excited to help me build the overflow box today. Looking forward to it. Just gotta go put my little daughter for a nap first.

More progress today: I build the overflow box. First I had to drill my 2 holes for the 1 1/2" drains in the overflow box. Here are both my kids helping me.

http://i600.photobucket.com/albums/t...g?t=1238276306

The worst part is cleaning silicone off dirty glass. I got the glass from someone who had ripped apart a fish tank so I had to use tons of razor blades and wire brushes to clean up the edges. Here is the mess created!

http://i600.photobucket.com/albums/t...g?t=1238276419

Finally all the glass cleaned up.

http://i600.photobucket.com/albums/t...g?t=1238276511

Here is the glass prepped with masking tape to get less smears in the silicone. I am using clear silicone. I know that the overflow box is not seen, but I still want it to look nice.

http://i600.photobucket.com/albums/t...g?t=1238276653

I cleaned all the edges with vinegar and newspaper (a trick from the guy who used to build tanks for Inter American or Bow Valley Aquariums). Here is the overflow box built. I just have to let the silicone cure and then razor off the edges. All the edges lined up flush and there are no air bubbles in the visable seams so I think that's the most important part.

http://i600.photobucket.com/albums/t...g?t=1238276919

Thanks for looking!

Looking good, surprising at how clean your cuts are, usually old glass doesn't cut so well, especially thicker stuff. Well Done! Is the extra chamber going to be for your external wavebox?

Thanks for the comments. Yes, the extra chamber is the external wavebox. it's 4 1/2" x 5" x 14".....hopefully it'll work. the actual wavebox dimensions are 4 1/2" x 4 /12" x 12". I think it'll work cause it's just displacing water at a set frequency.