when i made my own top i found that the plastic hinges were too large for the plexi, so i went to my local true value and got this super strong clear tape. Then i wrapped the end of the plexi in the tape,making the hinge end thicker . It only took me two layers of the tape to make it thick enough. Just make sure that all the tape will be covered by the hinge and you should be fine. I used the tank for about two years and never had an issue with the lid.