The Controller is very simple - a container with a float valve is connected to the line of units. A master reservoir filled with fresh water and nutrient is located on top of the float-valve actuated Controller. As the plants draw water from their individual reservoirs, the liquid levels drop causing the float valve in the Controller to open and draw fresh nutrient from the master reservoir. This automatically maintains the ideal nutrient level in all the interconnected units, simple, elegant, reliable and inexpensive.

Texas Controller Dimensions: 2'W x 2'L x 3'6"H Texas
Controller includes: 20 gallon reservoir with grommet Fittings Blue 1/2" tubing 20 gallon controller with float valve Fifteen 1/2" barbed tees Two 1/2" elbows