the material wouldn't make a difference. if you touch a 200 degree piece of glass or a 200 degree piece of metal or a 200 degree piece of pizza, you'll still feel 200 degrees of heat either way.I guess I wasn't thinking about how good of an insulator glass is. That makes me wonder if the titanium heaters are safe in the display tank, because the have less insulating properties. I didn't know if there would be risk of a fish getting burned.
the titanium simply gets hot faster than glass.