Put tabs with holes in them to put bolts thru at the corners of the angle iron pieces, rather than welding the frame together, you are bolting it together. That way you can adjust tension (size) more accurately.
I was looking through some stuff at the local home improvement center....you know...the way you do when your sent there by the wife for sink parts...and I noticed a product that might provide a solution to your problem. All it is..is a pre molded nylon finish joint designed to go along 90 degree tile seams. it has a rounded inside contour much like a finished sylicone joint would have but a squared off inner edge.
I realize that its not clear but if you syliconed this into each of the corners of your tank. The strength of the nylon combined with the added serface area of sylicone adheasive might act to keep the glass pannels from seperating under load and so save what could very well be a wonderful tank that I'd personally hate to see chopped into smaller pieces... Additionally I belive that because the bracing would be inside the tank rather than outside...the water pressure would make the bond stronger. The small strips of white inside the tank would be no more noticable than an external metal or wood brace.
looks nice, I think that people really overestimate the upkeep on large tanks though. Doesn't cost that much imo. Probably the most expensive part is keeping huge fish that eat tons. Pricey part is feeding the fish. Tank cost, power bill, and water bill are the least expensive part of my hobby. My power bill runs $100 per month running 5 tanks and 3 large ponds. All heated indoors. Water bill doing %40 water changes weekly on all tanks is $35 per month. So the fish upkeep is way more expensive IMO. of course i live right next to the missouri river the dams and water plants being so close might hvae something to do with it.
Oh the ponds are 55 gal, 350 gal, and 1100 gal, they are all uncovered in my garage. I heat the garage instead of heating them. Takes about 1500w to heat the garage whereas it was gonna take about 3 times that to keep these tanks up to temp.
Yeah i know but the food and stuff would be pricey, we don't pay for the amount of water we use here either, just a base rate, i live in a small town and only have 3 LFS's around here, and the prices aren't cheap, and no credit cards or anything for ordering online yet so i'm outta luck there, plus i would like to have an all glass tank instead of 2 plywood tanks, at least for a while.