Tunze 3155 optical sensor won't work until I let it touch the water

[Gaoweihd]

Hey everyone, I've had my 3155 ATO for about 10 months and recently it won't start the pump when the water level drops. This happens once everyday, I've found that nudging the optical sensor into the water for a second then moving it back helps, and it will work for serveral times until next failure. Cleaning it won't help, and the floating sensor doesn't stuck and work normally.

It's located in the return pump chamber, near the refugium, which has an all-spectrum light on at night. Does it seem to be a problem with the optical sense, or could the refugium light at night be affecting it?

 

[rvitko]

If a light emits infrared, it will affect the sensor, the sensor works on emitting and receiving infrared light.

 

[rvitko]

Also, be sure to do a thorough cleaning, a dull haze of minerals will blind the sensor, you may only be able to see this when the sensor is dry, one hour in vinegar followed by wiping it with a soft towel is the best way to clean them and get it off the magnet so you can check all sides.

 

[Gaoweihd]

Also, be sure to do a thorough cleaning, a dull haze of minerals will blind the sensor, you may only be able to see this when the sensor is dry, one hour in vinegar followed by wiping it with a soft towel is the best way to clean them and get it off the magnet so you can check all sides.

Thanks, I'll do a thorough cleaning. I think the light shouldn't emit infrared, it's a all spectrum reef refugium light.

 

[rvitko]

Generally anything made to grow plants, grow light spectrum, will usually include infrared.

 

[EeyoreIsMySpiritAnimal]

Thanks, I'll do a thorough cleaning. I think the light shouldn't emit infrared, it's a all spectrum reef refugium light.

Try keeping the light off for a day and see if the ATO works...

 

[Gaoweihd]

Generally anything made to grow plants, grow light spectrum, will usually include infrared.

Doesn't it seem contradictory that the ATO sensor and the refugium light are often positioned closely together in the sump? I would think this could be a common issue for reef hobbyists if so.

 

[rvitko]

The Osmolator has been around for 20+ years, way before LED refugium lights. Any optic sensor based top off will have this vulnerability and it is solved by simply relocating the lights and sensors so that the sensor is out of the path of illumination.

 

[Gaoweihd]

Problem solved! I relocated the refugium light, and then dip the optical sensor in vinegar for 4 hours, and the ATO has been working 100% reliable for 3 days now.