Glad I found this thread, very cool tank. I'm trying to do something similar with my new Waterbox, I just spent all day using silicone on magnets and getting them glued in...only to find the magnets wouldn't support the weight of the rock. Not even close. Wasnt a mega large rock either. I've read that you should only use ceramic magnets, but they are the weakest it seems, especially compared to neodymium