Sounds to me like he is COOKING these chicks. Using a 250W heatbulb over a small brooder like that. I had a 250W, I had to hang it almost 3ft above the floor of the brooder, so it would not get too hot. I bet the chick was gasping for breath. Get a THERMOMETER man, And see where the temp is. And stop with the aditives to the water. Just fresh cool, NOT cold, water everyday. And did I read it right, You have/had 18 chicks in that small rubbermade container. I bought 18 chicks this spring, I had them in a brooder I built that measured out at 4X5 FOOT, And that was looking kinda small when I took them out and moved them to the big house. Once you get your temp. under control, you better start building a new and BIGGER brooder.
Jack