Quote Originally Posted by simplechamp View Post
I have started using a sponge that's cut to fit into a small deli cup. I put in as much water as the sponge can hold and place it over the warm side of the tank. I make adjustments by how much polycarbonate is covering the screen lid of the tank.

The sponge helps the water to evaporate better than a regular standing dish of water. It's easy to clean, and if it gets tipped over it doesn't cause a flood or a mess.
One word...Bacteria...

Sponges are a breeding ground for nasty bacteria. I personally wouldn't use them in a Ball enclosure.