Taller than Garf recommends?
 

I want to build a 96"x36w"x30"h plywood tank with 3/4" Starfire glass,or acrylic (haven't yet decided), 3-5/16" ss rods as top braces. The top and front will have a 2" frame leaving a 92"x26" viewing window, Garf.org recommends not using glass over 24", this would leave only a 20"h window which I think is to small. Is Garf being overly cautious?. Are there any design changes that could minimize the 'risk' of using 30"h glass? Thanks

With 3/4 inch glass you should not have any problems. With 3/4 acrylic you will have bowing which will make it very hard to seal. Also PPG does not make 3/4inch Starfire glass anymore, you will need to have 2 3/8 pieces laminated together.

Kim

I think glass is going to be your only option anyway. I have never heard of any reliable way to secure acrylic to ply. I don't know what Garf is talking about...you can go 6 feet high if you use thick enough glass. Not starfire of course for reasons mentioned.

3/4" thick glass will work just nicely. Just make sure you coat all exposed areas of wood. Drill your holes first then coat very liberly. Have fun. I have built several out of ply and the next wone will be 72"x30"x26". I'm only going 26"h cause my arms can't reach any further :D and it'll be an inwall as well. Get some glue that is waterproof, not water resistant but proof.

I too have built some very large ply/glas tanks with good results.
I highly recommend that all pieces first be coated with a two part food safe epoxy paint on all sides and edges. Essentially you seal the piece so that it effectively is a piece of glass. Then drill as mentioned for screws. Assemble with aquarium silicone as usual and install screws. Finally just run a bead of silicone on the inside seams and smooth with finger unless enough was applied to assemble. Same as glass.
However I am assuming that you really want a super clear front pane which will be impossible.

Thanks for the replies, what is the thickest peice of Starfire available?, assuming it is 1/2" could I still use the same 30"h dimension?

With a lot of caution. I wouldn't . 3/4" is what is required.
Don't spend too much trime worried about the clarity of starfire and acrylic. I mean that clarity is great but let's face it, you are trying to build something cheap right? If not just build the whole thing from acrylic.
Just for your info, starfire glass(at least from PPG in Canada) is not as clear as it was previously. I have pieces of both the original and the latest, and the current star is in between regular glass and the old star in terms of clarity.

Remember that the water will be super clear as it flows all over your house after something made improperly breaks.

Here is where I got my 3/4" thick glass
[url]http://www.depglass.com/dec-lowiron.html[/url]

That's weird. Anyone know why the stopped making the thicker glass. Seems like they would lose a significant amount of money.