That's why I use the Stainless Steel dog water bowls sold by Petsmart. Solid, one piece construction with a rubber ring along the bottom. No issues at all, no slime, easy cleaning too. They have enough weight that the snakes don't usually turn them over. A little pricey, but I like them. They come in sizes that fit the needs of most snakes, from the little 3 inch to I believe a 12 or 14 inch wide bowl.

Jim Smith