I just got a baby girl ghost! She's really cute, but I'm having problems with humidity...

I am using coconut husk substrate and I think that it's the cause of my high humidity.

I had 2 main questions:
How do I lower the humidity from ~80%?
I was thinking of taking some of the husk out and replacing it with aspen.
Where should my hygrometer probe be within the tank?
I currently have it placed in the middle, closer to the ground level.