Heya, Recently ive managed to get My bps' tank temps up to the right temps by getting a CHE. But now im having trouble keeping her humidity up. While her humidity used to sit at a steady 70ish% it now drops seemingly minutes after I mist it to around 42%.

I don't want her to get a RI, so I was wondering if anyone had any tips on how to keep humidity up while having an over-tank heating element.

Here's some of her husbandry:

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!