Tips on keeping humidity up?

[Hugsplox]

4x2x16in PVC w screen top tank (ZenHabitats)
large water dish
Reptichip substrate, I used to use Ecoearth but that always got really dusty quite quickly so I switched her over to Reptichip.
small fountain in the corner to provide extra humidity.

heating elements: UTH on hot side, set with a thermostat to stay at around 90(F), CHE on colder side to keep her ambient temperatures up, also controlled by a thermostat, usually stays around 84(F). It gets really cold where I am and without it her ambient temps would be in the mid to low 60s.

Thank you for the help!

I can't for the life of me understand why Zen made a PVC enclosure with a full screen top. I have a zen enclosure for my bearded dragon and it's fantastic, but when Zen came out with the PVC version they said it was specifically for higher humidity animals, then put that 4 foot screen top on it lol. Makes no sense to me but that's not what we're here to talk about.

I agree with everyone else, get you some aluminum foil and duct tape, and cover up the bulk of the top. You want to make sure that you have good circulation in there but that huge screen lid isn't doing you any good holding anything in. I get the need to have the CHE on the cool side but I agree with Nikkubus I think you need to move that down closer to the warm side.

Also I don't know if anyone's suggested a proportional thermostat to you yet, but I would look into them. With an on/off I've found that I can maintain temps with the CHE but because it gets so hot and then turns off, and then takes forever to heat back up, and on and on all day it dries my enclosures out. Once I switched to a herpstat (not suggesting you have to buy this brand just what I have) it fixed this issue.