The low water indicator in the Aerogarden 3 and Space Saver 6 is a simple mechanical device with a green side and a red side. When the water level is OK, the green side is showing through the indicator tube; when it's low, the device flips over to show its red side. Sometimes, however, roots find their way into the indicator tube and prevent the device from flipping over - and then it stays green no matter how low the water is. Usually this problem can be solved by simply flushing the tube with running water. You'll need to remove the Grow Deck from the bowl and turn it upside down to run water through it. This can be hard to do if your plants are large, and you may need to make a point of opening the fill door periodically to check the water level until your growing season ends and the plants are out of the way.
