Just a little while ago, I was taking some pictures of my fish.. and as I was standing there, my son (2) got up on the couch and moved the lid to my AC110.. I simple told him, in a stern voice, "you don't touch my stuff, you'll be going to the naughty mat next time! Do you understand?" and he looked really sad and said, " yes mama"... so hopefully he'll get it.. he's never done it before.. lets hope it's the last..
I thought of this exact thread when he did it...
GL with your tank, and your son..