I was just gonna take the 29G aquarium lid, drill holes in the plastic part, and put it on my tank but it’s slightly too large to fit on the lower shelf. My mental plan is to super glue like foam or plastic in that divot and attach the lid onto that. I’d either super glue everything but the hinged part down, and maybe conform the front edge to create a loose seal to prevent escapes. I was also considering using velcro to attach the lid onto the tank. If I put velcro strips along the edges, would that be tight enough to prevent escapes?