They told me this
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Please turn off the unit, place the sensor so that the "Max" sensor is touching the water level, and turn the unit back on. Wait a few minutes for the unit to calibrate, after the lights are done flashing, the "Max" and "Min" light should be on. Move the sensor up out of water, wait for the lights to turn off one at a time, and the pump will then activate. Place the sensor back down to the desired water level, and upon reaching the "Max" sensor, the pump will turn off. Both "Max' and "Min" light should now be lit again. If the water level reaches the "Alarm" sensor, then the pump is too strong and is filling the water too fast. Turning down the pump will fix this issue. It is recommended to use the Tom’s Aqua lifter pump. If at any time during the start of this process and the "Alarm" is triggered, please take a picture of the back of the label on the ATO unit and provide us with this image, and a copy of your original proof of purchase or invoice, so that we may further assist you in this matter.
Hydor USA, Inc.
Customer Service
4740 Northgate Blvd [HASHTAG]#125[/HASHTAG]
Sacramento, CA 95834www.hydor.com
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