Hi, I made a waterer from a 6 gallon bucket and a serving tray under it. The serving tray is a perfect size to hold the water, and was inexpensive, but unfortunately it is made from aluminum and it seems the aluminum is degrading and I don't think that is healthy for them to be drinking now. Anyone have any ideas of what I can use for an 18" diameter round water tray? That is not aluminum? I can't seem to find anything online 

