The most common type of chlorine feeder is the erosion feeder. Solid, compressed chlorine or bromine, (In the Chlorine stick or tablet form) are placed into the feeder. Water flows over the chlorine pucks or tabs and dissolves it for a slow release. Chlorine or bromine in the form of Hypochlorous acid, is then released into the water. Erosion chlorine feeders are adjusted by a dial, to regulate the amount of sanitizer introduced into the pool water.
One of the common types of erosion chemical feeders is a free floating chlorine/bromine puck or tablet dispenser commonly called a "floater". Floaters are offered in various forms. Some are larger and hold larger 3" stabilizer tablets while smaller spa floaters only accept smaller 1" tablets. All chlorine and bromine dispensers will have an adjustable collar or similar design to allow for the user to control the amount of the chemical being introduced. The most common floaters will have a series of slits that can be open or closed to determine the volume of water entering and exiting the floating vessel. Proper circulation is needed for a chlorine or bromine floater. If the feeder remains on the surface of the pool structure for an extended period of time it could potentially cause a brown stain on plaster or bleach out part of a liner. Furthermore you will want to make sure that the floater does not dispense highly concentrated chlorinated or brominate water directly into a skimmer as the water will damage the equipment and plumbing over time.
Another type of erosion feeder is installed at the filter system. In the shape of a cylinder, clorinators (unlike a floating chlorinator), requires a certain amount of pressure supplied by the circulation system to dissolve the clorine or bromine tablets or sticks. The flow and amount of chlorine introduced into the water is regulated by a flow control dial, and also by how many tablets (or stix) are in the chlorinator at any given time.