So, I've noticed my baby ATB will occasionally lay part of its body in its water dish for a couple hours at a time. I am 99% sure it isn't mites. Does this mean anything?

Also, I've seen a lot of conflicting info about temps, in particular hot spots. Right now I am keeping the hot spot at 82-83º with an ambient air temp of 77º. I've seen some provide a hot spot of 83, 85, and even 90+. There is probably no single right answer, so I would just like to know what you keep your ATBs hot spot at?