Hello, I have ordered 5 water cups and I am going to put them in my coop for 22 chickens. I see most gravity feed systems use a 5 gal bucket for the tank. I was thinking I could use 4 inch PVC drain pipe. A 10 ft pipe will hold approx 6 gals. If I used 3 pieces of pipe that would me almost 20 gal capacity That would be more that I would ever need. A tee or elbow at the top to fill and all dropping to the bottom pipe and we are done and would last a lifetime. Any thoughts good or bad with my idea?