you have to realize that, that orchid bark is solid chunks...and not a soil type bedding...so it will not hold humidity as well as a ground coconut husk bedding. if you like the look of it(which is very similar to the ground coconut husk, except it has chunks), then you can always add a couple to a few inches of the coconut husk on the bottom, then add the orchid bark on top of that. the screen top is going to be IMPOSSIBLE to keep humidity in the tank. warm air rises, and with that....all of the moisture in the air. humidity is the moisture content in the air, not just a wet environment. so having a wet substrate is going to do nothing more than cause scale rot. you should cover that whole top with either Plexiglas, glass, plastic, or something that will not absorb moisture(like wood or a towel.) if not, you are going to be constantly fighting a battle you will not win. those are designed with vents in the doors I believe, so any other ventilation is not needed. cover the top and I think you will see a solid shed on the next round...and if you decide to use the ground coconut bedding, that will help even more. it is sold under the name 'bed a beast' and a few others, and comes in bags and bricks. get the bricks, you get way more for your money. the bricks require you to soak them in water, but all you do is squeeze out the excess water and put it in. this is awesome and I think you will be very happy with it. and it is also digestable if accidentally swallowed. good luck and let us know how she does.