sphagnum moss is really good to use for added humidity. to keep it clean and nder control i put it in a plastic bowl and put it under the light.. when humidity is fine or gets to high remove the moss
try covering the entire top with tinfoil just leave a 1 inch gap in the middle for airflow this should take care of the humidity issue.. if it doesnt turn off ur hotter light for a bit n let the humidity rize?