If you Google "aquarium hood", there are several dozen stores to choose from. If I were you, I'd go to Home Depot. Buy a piece of plexiglass that size-they cut it to your specs. Have them cut it in half. Super glue a couple pieces of flat, braided polyester straps on each side. HD also sells this plastic sheet that has holes all over it, that would be even better, as it allows for oxygen exchange. Or, you could have half solid plexiglass and half perforated. I got rid of the glass tops on my 125 gallon and made a 10 inch canopy with solid pine planks. I put cross-boards in for the light fixtures and I have 1/8" holes honey-combed to allow for ventillation, with a fiberglass screen to keep bugs and dust out on the vinyl coated hardboard top. You could use 3 inch planks to do the same. I even stained the outside with a verithane stain to match the trim on my tank.