Hey Roger or anyone who may know an answer to this problem of mine with the optical sensor. I purchased a Tunze 3155 and set it all up. When I turn it on, all 4 lights turn on, then the too low light turns on (Red, which means the optical sensor failed, correct?) The sensor is clean, dry, and not in the water before the pump turns on for 15 seconds. No matter where the water is in the tank, it always reads "level". Half submerged, out of the water, inches above the water, it always reads the same. It never tops off my sump. Hope you all can help
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