thanks for the comments, i appreciate it.
jim ,i wish i had taken photos of the steps i took in making the case but i didn't. here is a side view of the case
i built the diorama to fit the case. as i said i used 4 frames i picked up at the dollar store, my favorite hangout to find modeling supplies. construction is pretty straight forward. i used full pieces of glass that came with the frames for the top and front. the cardboard backing was used for the back and bottom. 2 full pieces of glass form the last 2 frames were used for the sides. measure the width of the frame taking into account the thickness of the front piece of glass and the back piece of card board. mark your glass and draw your line.i used a corked backed ruler , helps keep it from slipping on the glass. i used a cheap glass cutter i picked up at the local hardware store, think i paid 5 dollars for it. tricky part is scoring the glass. you can only score glass one time. do not try to score it over and over ,it ruins the cutter. use even pressure when you make your pass with the cutter, start at the very edge and run it off the edge. take the ruler and place it under the glass and line it up with the score. then press down on the glass, should break clean. use some wet/dry paper to smooth the edge. take the frame that will be the top and silicone the glass in place. once dry you can now assemble the cases sides. if all the measurements are right .it will fit nicely in place. if your glass is off a bit. you can always trim the back panel . if the glass is short. well you'll need another piece of glass. run a small bead of silicone around the inside edge of the frame and fit the pieces in place, tape the corners to keep the case square. once dry, your case is complete. i used small screws to attack the diorama into the case, you can silicone everything and make it permenent ,but i've already taken the duo out once and redone the water, so i'd suggest to give yourself a way into the case if needed down the road. i was going to use styrene and add corner pieces but i like the clean lines of just the glass. you can also use a full piece of glass for the back if you want a full 360 display case. sorry for the novel. i tend to ramble.this is really very easy to build. i practiced cutting a couple of spare pieces of glass to get the hang of it.you can't beat the price for a IMHO a pretty nice look case. hope this helps