Osmolator Troubles

[hatfielj]

I just set up an Elos Mini and I'm using a Tunze Osmolator for top off. I'm having trouble with the water level sensor though, basically the water doesn't stop pumping when the level gets to the tip of sensor. It stops only after getting to the top of the sensor. Additionally, the pump will turn on even when the water level is still high and cause the sump to overfill so that the water level alarm goes off.
I know its not the unit itself, because this is actually the 2nd 3155 osmolator I've had on this same tank/sump set up. Its positioned in the last chamber of the sump like its supposed to be. It seems to be set in a relatively calm spot.
Could this be due to micro bubbles? Is it a faulty sensor? I've never had this problem with my other tank that also uses an osmolator.
Thanks for any help.

 

[hatfielj]

I've been testing the system today and I'm convinced that there must be something faulty with the eye/sensor. If I pull it out of the water it definitely turns the pump on, but if I put it back in the water, even fully submerge it, it doesn't reliably turn the pump off. It usually runs with both the green and the orange light on and only randomly turns the pump off long after its already fully submerged in the water. Is there anything that can be done about this. Its brand new and if I can't get it to work I'm going to have to return it.

 

[rvitko]

It could be any of three causes.

1) Microbubbles, the sensor cannot differentiate between being dry and bubbles.
2) Faulty sensor
3) Magnetic field near the controller. If the controller is near a ballast, magnet holder or large pump this will close the relay and cause it to run.

If you are fairly certain it is a faulty optic sensor send it in and I will replace it, keep in mind though that new sensors have a strong affinity for bubbles, new plastic is hydrophobic, it repels water and attracts air. A rinse in hot soapy water will help alleviate this.

 

[hatfielj]

I'll try rinsing it a few times and try to rule out bubbles as a cause. I actually tried putting a plastic bubble gaurd around it to try to keep any bubbles away from it and it didn't seem to help.
Additionally, I tried to operate the sensor using a bowl of water, with no bubbles in it obviously, and it still had issues with not shutting the pump off appropriately.
I'll liking be sending this in. Thanks for your help.