The AQUAvalve is a simple and effective watering device. It is supplied with all AutoPot tray systems. Once connected to the water supply the AQUAvalve will control the flow of the water to the plants by simple gravity pressure from a tank or reservoir. No pumps or electricity or timers required. The AQUAvalve will open and allow water to fill the tray to the preset level of 20mm. When this level is reached the AQUAvalve will shut off and prevent any further water from entering the tray until all the water has been consumed by the plants. Once this has happened the AQUAvalve will open and allow more water to enter the tray. As the plants grow the AQUAvalve will open and close more often in line with the needs of the plants. Keep the AQUAvalve and the lid clean and free from obstructions and it will help you water and feed your plants for many years.