Although it was not our plan, I think our excitement about the tank and trying to engage the kids in the hobby resulted in: 1) reduced novelty and subsequent curiosity about the tank, 2) reduced activity near the tank (maybe the feared if they went near the tank, I would make them talk about it). So, I guess try to burn your kids out on the hobby, or at least remove the novelty or taboo about it. It worked for us, and out kids who are 3, 5, and 7.