If you'd like to make it a bit nicer looking and easier to deal with take the lid off, get some packing tape, and tape off the lid from the inside, sticky side towards the vents. Add a few strips, see how it goes for a few days, add or delete as necessary. I'd also recommend taping so that there are openings on either side to promote air flow a bit more evenly. If you cover one side it could create more stagnant conditions on that side of the tank. How much I can't say, I might be overcautious, but it makes sense in my headI already put it!
But it looks ugly as heck...
Just make sure no sticky part of the tape is left exposed. You might only be able to tape the very top part of lid and not the edges where the vertical vents are but that's fine.
And what about the enclosure above it?
Heheheheheh
