Problem 1
The tank was used to house reptiles previously, so there was no need for the middle support bracket, it was broken off. I'm using it for fish of course, so I needed to replace it.
Materials:
1 piece metal flashing 3 inches wide and as long as your tank is wide + 3 inches (my 40 gallon is 12.5 inches from outer edge of the trim to outer edge, so I used a piece that was 15 inches long)
2 small squares of craft foam (about 2x2)
glue (optional)
Tools:
rubber mallet
straight edge
clamps
tin snips
box cutter (or other knife for scoring)
tape measure
square
Assembly:
1. Make sure that your flashing is square, trim off any excess to make it square
2. Using your straight edge and knife, score the flashing at lines A and B on Image 1.
3. Fold C and E over D, use the rubber mallet to pound the entire thing flat.
4. Clamping the straight edge to your work surface, bend the metal up to a 90 degree angle along the dotted lines on Image 2.
5. Stick craft foam on the insides of the bent part of the bracket to make sure that it has a snug fit. (my foam had sticky stuff on it, so I didn't need glue)
Image 1

Image 2

So there you have it, a bracket that will support your water weight, won't slip off but is removable if you want to.
Mine cost me absolutely nothing as we had the flashing and the craft foam hanging around the shed and house, and we had all the tools needed. It took an hour or so and a couple mistakes to get it right, but in the end it works great.
Problem 2
Said tank also has no hood, and now that my bracket is on there, a standard hood won't fit very well. My plan is to make two smaller pieces of hardware cloth that will sit just inside the rim of the tank, on that little ledge thing.
I don't have hardware cloth of the appropriate weight here at home, so I'm going out to buy some today hopefully.
