I want to be able to keep everything "fishy" under the tank, including an area for electrical. As the tank is 6ft I figure a 3ft sump would suffice and still give me enough room otherwise.
I got the glass cut for a 36X18X18 so potential for 50gallons. Of course when I got the glass cut the first time I forgot to take into account the thickness of the glass itself, so my sides were about 3/4" to wide. After a few practice tries I tried cutting 1" off the sides. The first one went well and straight, the second was good but a bit like a country road. I took out the old belt sander did what I could to clean it up. I siliconed everything together and it was pretty good, the slight curve of the cut made the side piece pivot at about the 1/3 mark on the way up. As I was making final adjustments the top or the bottom would pull away leaving some air bubbles in the silicone. Being a wood worker and having plenty of bar claps I simply clamped the bottom then applied some pressure to the top and things looked better. Of course a second clamp at the top would make things look better still. A couple gentle twists and all air bubbles were out. I sat back and admired my work and about 30 seconds later pop. The long piece broke. Back to the glass shop and attempt #2 but this time I had new sides cut as well.
I cleaned all the old glass with razor blades and a wire wheel. Once things were clean I dry fitted, re-taped and glued it up. I didn't end up using the corner clamps, got a good deal for 4 at LeeValley but I am happy with the GE 1200.
I just used duct tape to pull it together and it held. Seams were good with almost no bubbles.
I let the tank sit for about 3 days and it looked like there was a small bubble that formed about half way up one side. I did a leak test and the bubble grew until I realized it wasn't a bubble in the seam but a fault or fracture in the glass. A small dime sized portion of the class popped off. I thought for sure the tank would blow again but it held. Left water in for about 2 weeks and everything A-Ok. So I am not sure what to do from here. I crazy glued the piece back in, but I know structurally that does nothing. I was thinking of siliconing one of the small 1" strips over top just to give it some added strength. The water line won't go up to the point but I don't want a weak sump.