[Cuby2k]

For those of you thinking a solid piece is best for the bottom consider the way glass is cut.

If a standard cutter is used the crack line would not permit the inside cut that is required. If a water jet is used the cut could be accomplished but due to the loading of the glass, handling would be extremely difficult and very susceptible to breaking. And the cost of a single piece of glass that size would be out of site. It would take a solid piece of 3/4" that starts with an 8' x 8' solid piece! Talking into the thousands of $$.

On the other hand, consider the seams on the outside corners of your tank, they take much more stress than a butt joint on the bottom. AND if two pieces were used in the butt over a cushy surface the ability to flex even if it's minimal could work to the advantage. A third lap piece would be added over the bottom butt joint after the sides have been placed and effectively increase the thickness of the glass at that point to double.

As fas as the silicon holding, have you ever tried to remove it from the glass after a full cure?

I hate to admit this but just about a year ago I filled my 180. I have two 2" holes drilled in the bottom for my closed loop and one of the bulkheads was undersized (different manufacturers). After planning for over a year, taking my time, reading and studying, etc., I was finally ready and one little old mis-sized bulkhead was not about to stop me. Sooooo, I filled the gap with type I silicon and it is holding!

Now I hate to admit that and certainly I would not advise it but a well placed silicone seal over a clean glass surface is extremely durable.

Coralnut, I am starting to think that my dream tank will now be a built in place "L" shaped. I hope you are able to continue this regardless of the time it takes and share the results with us.

Anyway, just some more food for thought.