Hello all, I have a baby pixie frog in a 20 gallon glass tank with about 4-5" of coconut fibre substrate. I was wondering the correct location to take the humidity reading? I'm using a Zilla thermometer/ hygrometer and the probe is about an inch above the substrate. The humidity seems to increase and decrease quickly even though the substrate seems to remain moist. Is there a hygrometer that can be buried in the substrate? Is that level or the air humidity level more important? Thanks in advance!