Flow switch plug-in controllers from Harwil Corporation can help manage chemical feed pump activation. When there is water flow in the waterline, the controller switches the chemical feed pump on, then off again when the water flow stops. These controllers can be used on 3/4- to 6-inch pipe and provide 13 amps at 120-volt receptacles that are always on and also switched. Three different flow switch and plug configurations will fit any application, making installation quick and simple. These controllers can be used to ensure liquid flow for other applications where sufficient water flow is critical, such as chillers, heaters, and UV and ozone systems. 800/562-2447; www.harwil.com.