Why does an ebb and flow tray system have two fittings?
First of all the common names of those two fittings are a fill/drain fitting and an overflow fitting. The fill/drain fitting is a fitting that is attached to the pump and serves as the inlet for the water filling the tray and also serves as the outlet for the water to drain back into the reservoir. The overflow fitting consists of a number of different plumbing parts and acts as a watering level regulator. The concept is quite simple… you have a tray that is suspended somehow, or sitting on top of, a reservoir. Now the pump turns on and begins pumping water into the tray and the pump will stay on as long as the grower has determined the watering cycle should be (usually 30 min.). As the water level rises in the tray it reaches the top of the overflow fitting which then allows the water to spill back down into the reservoir. So you have now filled the tray with water and you are maintaining that watering level by means of the overflow fitting, which does not allow the water level to r
