Humidity issue

I have a new baby ball python. about 3-4 months now. i have her in 20 gallon long tank with a mesh screen cover. has an undertank heater and a climbing branch with a hide on each side. I use a day heat lamp of 100 w but always check on it to make sure it doesnt get too hot. at night i use a 75 w. black heat light. im having a little issue with humidity. the gauge says 40% almost all the time i bought some sphagnum moss and put some in the hide and around the tank and mist daily put the humidity only seems to go to 50% the most. shes currently about to shed anytime her eyes just cleared but maybe i could get some ideas on keeping humidity up...thanks

cover half of the screen top with a towel, that usualy keeps it a bit higher. or use a large water bowl directly under the lamp

Are you using a dial gauge or digital? The analog dials are notoriously inaccurate. This being said, your humidity could be even lower than you think since you have a screen lid. Definitely cover 3/4 or so of the lid to help hold humidity in - I used plexiglass taped on with electrical tape (outside the lid).

If your house is 75-80 degrees you really should only need the undertank heater. The dome lights will suck the humidity right out of the air and make it very hard to keep. I keep my room at 78 and only use undertank and I have a room humidifier in there to keep the humidity up.. Hope this helps!

I have best luck with a damp towel. Others also suggest having a piece of plexiglass cut.

ok I will try these ideas...thanks for the advice everyone

40-50% is fine unless a shed is expected than you can just place some moss in the hides for the duration of the shed and not have any problem.

The dial type with paper cards can be an issue the digital types with open sensors and resistive sensors can be an issue too. Metal cards with bi metal springs are very tough and can be corrected if they go off. They are more than the cheap pet store ones but less than the digital ones. The digital ones are great as long as you never allow them to become dusty or dirty or pull alter the cord in any way. They are quite frail all in all.