I just came across your thread. Sorry to hear of all the mishaps and losses.
I have had a similar experience with newer faucets when trying to fill a tank with a python. Some new faucets use quick connections with o-rings and once the python is connected it creates enough back pressure to overcome the o-rings. I use the kitchen sink to fill a 5g bucket that is sitting in the sink and then a small pump to pump to which ever tank I am filling. Your tub would be ideal for this type of gerry rig.
I have had aquariums since before my children were born and have taught them from very early on not to play in the tanks. My mother visited on a number of occasions and I would come home to find her encouraging my children in disobedience.
I didn't punish my kids for these times but mom worked her way into being persona non grata with reckless abandon not just over this.