Sure thing, Dave. The tank is constructed as a fiberglass reinforced plastic box with portholes cut out for the viewing panels. This is even stronger than an acrylic tank for the base frame. You then have the option of using either acrylic or glass viewing panels.
I don't know the details of how the viewing panels are sealed, but the main idea is that the brunt of the force on the panel is borne by the FRP frame. All the seals have to do is prevent water leakage; there is not a silicone or adhesive that is having to serve as both the structural element preventing the panels from bursting apart and also serve as the waterproof membrane.
The glass is 1.5" thick, three laminated layers of 1/2" starphire. I think the tank could have been built with thinner glass from a structural standpoint, but I also specified that the glass be thick enough to ensure zero visible deflection when filled.
The braces are pegged to the FRP frame with 5/8" stainless bolts. These provide additional strength to the frame, allowing for the top frame to be thinner than with a pure eurobrace design. Waterdog would typically use a single FRP panel with cutouts, no separate braces, but I did not want the shadowing caused by the FRP cross beams.
Regarding lighting, I will be using a PAR meter once things are set up. For now, I'm trusting that PAR will be okay based on a few data points: 1. Ecoxotic's assurances that these pendants are good for SPS level PAR at up to 72" water depth; 2. these lights are used in public aquaria for planted tanks up to 40' deep. Also, if PAR should happen to be a bit lower I'll be okay with this so long as I get good PAR for at least the top 30" of depth.
I didn't seriously consider Orphek mainly because they only offer up to 100W. I do have a couple of the Orphek Nilus panels that I might use over the frag tank, and they are very nice, though not quite the same build quality as the Ecoxotics.
