The WaterFarm Controller Kit (8-16 plants) is eight WaterFarm module units connected to one General Hydroponics Controller: and integrated 13 gallon reservoir and an 8 gallon controller unit. The Controller will keep each unit topped off with the correct level of nutrient for low maintenance. The kit is powered by GH's Dual Diaphram Air Pump, and includes all the necessary hardware , supplies and General Hydroponics Flora Series 8 oz. nutrients. The grower can arrange the WaterFarm units in a design that is suitable for any environment. Pack them tight or space them out for your growing situation. The WaterFarm 8-pack is the system for big growers. Please note that (1) 50 liter bag of Grow Rocks is NOT included.