HCA: Hermit Crab Association

I recently got a new 10 gallon crabitat for my hermies and I am having a horrible time trying to maintain the temp. and humidity. I have a substrate that locks in humidity, to get it going I sprayed it and now my humidity levels are 85%-90% and the temp. is around 75 degrees. I keep a towel on top of the mesh lid to keep the temp. steady but then the humidity gets to high. Is this too much humidity? How can I keep my levels more stable?
Thanks

The humidity should be around 80%. You don't need to spray it really. Are you checking the humidity and the temperature near the substrate? What are you using for heat? What kind of crabs do you have? These can help us give you some more help

If you put siran wrap on the mesh lid with a tiny hole or three for circulation, you should have no prob with humidity. Make sure to moisten the sand all the way through as spraying will only dampen the top.

I have a temp. and humidity thermometer to check the tank levels. I don't use anything for heat, I rely on the substrate to keep the temp. and humidity up. I have three purple pinchers (the ones you buy at the pet store)
Thanks for your help!

I have a 10 gallon and no heat source, and I keep my heat and humidity pretty stable at 85-87% humidity, and about 70-73 heat (which is a little low, but it's as good as I can get without the heat source). What I did was buy a simple mesh cover for the top, then covered it all with seran wrap (I taped it down on the sides). I then picked up one of the corners to allow air to come in and out. For humidity, I make sure that both my water bowls are at least half-full at all times. I've also poked holes through my substrate and added water that way to allow moisture, careful not to add too much. Finally, I have a moss pit, which has done wonders for keeping humidity up. Just make sure that stays moist and you shouldn't have any problems--I don't.

Ya, I have a mesh covering on top and I put a towel on top and lift one of the corners up, which seems to be working okay.

Is it keeping the humidity up?

Yes, it seems to be working quite well.
I think my problem is solved. (lets hope)