Bricks are a good idea, but there's no space above the element for anything.
I've been thinking about the lava rocks, bricks, etc idea, but it seems like the water pan would serve the same purpose in that once the water was heated, it would help maintain the temp like bricks or lava, with the added benefit of helping keep the food moist. It would be easier to jump-start the heating process by pouring a tea kettle of boiling water into the water pan, too, instead of heating rocks from cold to hot.
I put hot water into the water pan, but it wasn't boiling. Maybe that's part of the problem. I'm also wondering if the factory water bowl is too big and blocks the heat, although since the bottom is rounded, the heat should be directed up the sides so that's probably not a huge factor. Or maybe I put too much water into the pan.
The more I think about what I don't know, the more things I think of that I don't know.