I have found issues with keeping my humidity up, but currently have it down to a science. Now what works for me, might not work for you. Just keep that in mind. You will have to trail out a lot of different stuff to find your own way to keep your numbers.

Now with the information given, I will suggest ditching the heat lamps and replacing it with a 100W light on a 12.5 hour cycle. BP dont really come out of their hides much, so I would concentrate all of my time to getting the numbers perfect in both your warm and cool hides. By doing this, you will correct for ambient temps/humidity.

What is the temp inside of your place? Do you spray the tank down? How often? What do you use for substrate now? Is the top of the tank covered with some plastic? How big is your water bowel and where is it located in the tank? We really need all your information to assist you properly.

Here is a copy and paste of a reply I made to a different post concerning humidity where I have gave a list of my set up and results. Just copy and paste the message and change the information to your own information and we will have a better idea on how to assist you. The more you can provide, the better:

"Here is what I have set up, try out different techniques to obtain your numbers (my BP is in shed, so that is why the humidity numbers are high):

-my apartment heat is at a constant 80
-she is in a 30g tank away from any heat vents
-one UTH that covers about 1/3 of the tank
-thermostat *this is IMPORTANT* regulating belly temps
-one light fixture with a 100W light set to a timer for 12.5 hours a day
-bi-daily misting
-daily water change in the 9 inch ceramic bowl
-a 1.5" to 2" inch moss bed above the UTH with aspen covering all
-plastic covering over half of the top

RESULTS:

-my temp/humid numbers for my warm hide is 91-92/75-80%
-cool hide 80-87/70-75%
-ambient temp is approximately 87-90 day, 80-84 night with humid numbers staying between 65-75%.

Once she is done shedding, I will be removing all the substrate and only using aspen. I only throw the moss in during shed to increase the humidity. I can keep my normal humid/temp numbers fine with 1 daily misting and a water change (logged anywhere from 55-65%). I was having the same issue with the low ambient temps until I started running the 100w light for a 12.5 hour cycle. Be sure you are regulating that belly temp with a thermostat, mine burrows down to the glass all the time.

Also, check the numbers in your hides. Concentrate on getting your numbers perfect in the hides and in turn you may improve your ambient temp/humid numbers.

Just keep in mind what works for one, may not work for another. Keep plucking away at it and you will find a way to get your numbers. Keep a log too,(log everything) this will help out a ton in the future.

Good luck with your work and research! Hope you find your numbers soon! Cheers!"

My little one has finished her shed, which came off in one piece. No stuck shed anywhere on her. I have since cleaned out the tank, replaced the substrate with only aspen (only about 1 inch) and still preforming daily water changes and misting. My numbers are recoded between 48%-64% since the change over. They start off high after the misting, then drop down during the night. If for what ever reason the tank is down below 50% when I get home from work, I give it another mist to bring it back up.

Hope I can help out more, Im just not sure of your set up so I cant offer any advice other than switching out the heat lamps for a 100W light on a cycle. Hope you can find your numbers soon!

ps - how big/old is your bp?