Posted: Sat Jan 17, 2015 2:27 pm Re: Musk Turtle Shell Health??
85 is a bit too high, and 73 is a good temperature (most people shoot for around 75-78, but like I said, I've seen some Adults okay at 65).
Personally, I don't use any substrate and my turtle is fine. I just include several fake plants for cover/enrichment. If you really want to use substrate, however, sand is popular and does well for spot cleaning (waste just sits on top until it gets siphoned out). The musks also like to burrow (and sometimes sleep) in it.
It's great that you're looking into improving the basking area. I'd like to suggest avoiding the "Zoo Med Floating Docks" because they will eventually sink under the RES's weight, unless you strap one on top of another. If you go to the "Indoor Habitats" forum area, you'll fine some fantastic DIY ideas from other forum members!
New RES will sometimes take a while to bask, but it sounds like you've been waiting for a while. Try putting some pellets on the basking area, and leave the room. If they're gone when you come back, then you can be pretty sure the turtle went up to eat them (and probably basked for a little bit). Just keep an eye out for any shell fungus from not basking. And yes, classrooms aren't the ideal turtle housing areas--low-traffic/no-traffic is always best, but at 6 students I don't think it's too disruptive.
I'd love to see a picture of your setup! How big is it, and I'm still a little confused as to whether or not the turtles are living together?