Tunze Osmolator ATO Optical Sensor Replacement

Reeferman81 · Apr 29, 2026

I have an issue with my Osmolator where the optical sensor and the float switch do not cut it off and it times out. I have tried to clean it without luck. Can I send it in for repair?

rvitko · Apr 30, 2026

This would be extremely unusual, we should start with some basics, can I get some photos of how the sensors are installed? If this is an installation issue, I will not find it here and then shipping will be a waste of money and time. The float is a magnetic switch so it can be pinned on or off by nearby magnets or misaligned or wrong magnets. One common scenario I see that will cause this is having the optic sensor upside down.

skrtchsr · May 19, 2026

It's blowing my mind the length of time rvitko has been supporting this thread. Genuinely amazing. I'm not sure if this is the best way to do this and feel kind of bad for lumping on. But my sensor failed, seems a small electrical burn spot in it like a capacitor popped or something. At any rate, I bought it on bulkreefsupply about a year and a half ago and its worked great until now. Let me know if you want me to send you my BRS receipt or where and how I can order just the sensor as well. I only see one on the site for around $140 which seems odd for just the sensor. I appreciate you for keeping up with the product on this thread all this time.

rvitko · May 19, 2026

What Osmolator do you have? The Osmolator 3 has a 5 year warranty and that is the only model with a $140 sensor but that is because both sensors, controller and magnet holder are all one sealed unit so it is the entire assembly.

skrtchsr · May 19, 2026

rvitko said:
What Osmolator do you have? The Osmolator 3 has a 5 year warranty and that is the only model with a $140 sensor but that is because both sensors, controller and magnet holder are all one sealed unit so it is the entire assembly.

I have the Osmolator 3