Tunze 3155 - Do I have a bad sensor?

[AlexKintner]

I've had a 3155 in a new setup for a couple months now. From the beginning I've noticed that it will engage properly for a period of time (typically a few days), and then simply stop working. The LED indicator will read 'Level', but the pump never engages. At this point if I clean the optical sensor with my hand and some sump water, it will wake up and fill back to level. It will typically work again for a few cycles and ultimately fail again. It's sitting vertically using magnetic holder in the return chamber of an RS-75 sump.

Is this thing broken, or might I be missing something?

Appreciate any suggestions

 

[DED65]

I would take a guess and say that the sensor needs to be cleaned more often since it works after you wipe it. Have you tried cleaning the sensor with vinegar or citric acid?

 

[AlexKintner]

Thank you for the reply... I'll try some vinegar.

Strange that it's done this from the beginning. I don't think it's ever made it a full week without failing. How often do people clean these things?

 

[DED65]

I try to clean mine every water change. It never really gets any build up on it, but that would depend on any precipitation that may be in the tank.

 

[rusty hannon]

i dont know if its exposed to any light source but a thin layer of algae would do it as well

 

[AlexKintner]

Appreciate the responses

So I think I've figured this out, and it turns out to be a novice mistake unrelated to the ATO. I found that the water level in my sump was too high... resulting in a rather stagnant return chamber. This created a permanent film which mucked up the Tunze optical sensor.

Simply lowering the water level led to a nice cascade effect into the return chamber and much improved water movement. Time will tell if this was the fix, but I'm feeling confident.

Thanks again all