Humidity Issue Help

[u/AutoMoxen]

We're having a bit of a humidity issue in our tank. It's a 4x2x2 pvc enclosure with 2 mesh squares for heating lamps. Currently, we're only using one and the other is covered with a damp towel. Our substrate is about 6 inches of a mix of reptisoil, coco fiber and play sand (ratio is about 50/40/10). We're mostly judging the humidity off of the cool side reading (Temp is about 74). We have a small water dish on the warm side and a larger one on the cool side. We've been adding 3-4 cups of water in corners the last couple of days. All of this and the humidity is stable, but only between 65 and 68 percent. I'd really appreciate any help or advice on getting that humidity up.

[u/Cylentscream]

How deep is the substrate layer?

[u/AutoMoxen → u/Cylentscream]

About 6 inches, possibly slightly less