Thanks for the heads up on heaters, we bought them a few months ago before knowing very much. Hubby has to go pick one up today when he gets my Zebra Mantis for my refugium later in that day. I know he will be asking which ones can be submersed since it was never a question before. If the box says don't do it, I follow what the box says. Mind you most men do things and consult the instruction when they have a small hang up.
Getting the "I told you so" from hubby about the heater exploding is one thing. My "I told you so" for zapping my tank of livestock would not be so sweet in the end