It may be kinda dumb but I found these "boot trays" at target in their little dollar isle and they are perfect for a large shallow water dish! They are made of a thick black plastic and have a diamond plate pattern on the bottom for traction. Only about an inch deep or so but that's all a tortoise needs! I bought 12 of them...I plan on putting them under the dogs food and water and then have some for spares for the tortoise enclosures. I might even use one for their food bowl.