Okay, please look over this caresheet http://ball-pythons.net/forums/showt...ius)-Caresheet
The hot spot should be between 88-92, and I keep my ambient temp around 80. It may help if the hides were identical and tight fitting. I use these:
http://www.reptilebasics.com/hide-boxes

I have never heard of a ball python swimming, so if you are seeing him soak often I'd check for mites. Be careful the substrate doesn't get wet, damp substrate can lead to scale rot and bacteria build up inside the enclosure.

As for temp/ humidity readings you can use the accurite indoor/outdoor ones which aren't too bad for the price, a lot of people use them. Also if money isn't an issue, you can get a temp gun. My temp gun is my favorite and most used tool.
http://tempguns.com/

Also, how are you heating the enclosure? Are you using an under tank heater (UTH) or heat lights, or both??