Abstract: A chemical feeder having a collection reservoir and an erosion reservoir located within and spaced from the wall of the collection reservoir. An elongated cylinder is supported on the collection reservoir and the lower end of the cylinder is located in the collection reservoir. The collection reservoir has a water discharge outlet and the erosion reservoir has a water inlet with a valve to control the flow rate of water into the erosion reservoir. A canister containing solid chemical sanitizing elements is supported in the cylinder and its lower portion is located in the upper portion of the erosion reservoir. Openings are located in the lower end portion of the canister so that solid dry chemical sanitizing elements located in the lower end portion of the canister can be contacted by water in the erosion reservoir to erode and dissolve the solid elements to chemically treat water flowing out of the erosion reservoir into the collection reservoir.