Habitat - Indoor :: How High to Make the ATBA Walls?

[ChangTang]

So I'm starting to get some ideas for my semi-above tank basking area. This is the look i'm going for...
- credit to octopusgirl8

So I'm going to use a cork bark slab, and put it as far high as I can in the aquarium like it's pictured so I can utilize all my water space. Instead of having all 4 sides be acrylic / plexiglass (EXPENSIVE!), I'm going to do the back, and sides in plywood and the front in acrylic so we can see him/her basking. My question is, how high do all the sides need to be? I'm not planning on having a top, if i do, it'll be eggcrate, but that'll be a decision for the future. I was thinking 12"? Or would I need to go even higher at 18"?

Also, to bind the plywood and acrylic together, would I use aquarium silicone? or would it be safe to use a different kind of glue? My 55 gallon tank has a divider on the top in the middle (like i think all 55's do) and I'm using the one half like they ^ did and putting a hood and florescent strip on it.

Thanks for anyone who helps!

[vear]

Well, my old ATBA had 12" walls, and it was fine since Tomi was 5.5" or so. However, I saw how much he stretches and it started making me nervous. I figured once he grew a little, he'd figure out a way to get out. Also, the ATBA kind of looked weird with such high walls. Long story short, I redesigned the ATBA with shorter walls and an eggcrate top. Looks nice and makes me feel better.

About the plywood, I used angles to hold the sides together. They're screwed in with nuts and bolts - so they're not going anywhere I don't trust glue! =) (you can drill into acrylic also, you just need a good bit - this is how I made my ramp).

[ChangTang]

Well the piece of plywood I found laying around is 1/8". And to minimize costs I'm going to try and get a thin piece of acrylic. I may just use like gorilla glue and use braces as shown, but I don't know what anyone else thinks.

[steve]

If your turtle will be in that type of setup, 12" would be fine.