The IWS flood and drain watering system is a highly developed, hybrid ebb and flow system that works by flooding a series of pots from the bottom up. This controller has two magnetic float valves that control the levels at which the pots "flood" and can be hooked up to a IWS timer for much more precise control over your plants' feeding cycles.
Use in conjunction with the specific IWS reservoirs, they work with the internal pump already installed in these tanks.