Thanks for the ideas guys! I ended up getting a couple ceramic block magnets at the hardware store since that's all they had for magnets. They're doing the job for now but if Glurmo decides to climb on top of it I think it will slide to the bottom. But at least it wont fall! I'm thinking of ordering earth magnets online at some point. The would definitely do a better job! Oh and to keep the magnets from scratching the glass I covered them in clear packing tape. I was pretty proud of that idea LOL.