I have an older 75 w/ no center brace. It didn't come with a glass top either. Here is how I remedied it...
2 pieces of plexi-glass, 2 pieces of aluminum angle iron and some stainless machine bolts w/ nylon nuts.
The tank was 1/2'' glass though. If it wasn't and I needed a center brace, I'd probably get some 3/16 x 2'' aluminum flat bar, slip it in a vice and pound it over to create a lip that would hook on the outside of the tank.
I tried to make the plexiglass top at first without the angle iron and eventually the heat of the lights warped the sh|t out of it. I also tried fastening the angle iron with just silicon too, but eventually that let go as well.
2 pieces of plexi-glass, 2 pieces of aluminum angle iron and some stainless machine bolts w/ nylon nuts.
The tank was 1/2'' glass though. If it wasn't and I needed a center brace, I'd probably get some 3/16 x 2'' aluminum flat bar, slip it in a vice and pound it over to create a lip that would hook on the outside of the tank.
I tried to make the plexiglass top at first without the angle iron and eventually the heat of the lights warped the sh|t out of it. I also tried fastening the angle iron with just silicon too, but eventually that let go as well.
