Need help, Tunze Osmolator pump failure?

reefshawn · Aug 30, 2019

I just bought a new Tunze Osmolator ATO a few days ago and it has been working great. This morning I checked my reservoir and it was maybe at 1/4 (pump still fully submerged) so I decided to top it up. I unplugged the Osmolator and pulled the pump out, moved the reservoir out and filled it up, then dropped the Osmolator back in and plugged back in.

Here’s what’s happening... I can hear it humming like it’s turned on, but no water is pumping. I’ve tried unplugging and replugging, jiggling the pump a bit, moving the hose and making sure it isn’t obstructed... nothing. Just noise for maybe ten minutes and then a fail light comes on on the controller.

Does this sound like the pump has failed, the controller has failed, or is there some trick I need to do to re-prime the pump? Thanks!

reefshawn · Aug 30, 2019

Well never mind... maybe? After waiting quite a while I tried one more time unplugging and plugging back in and now it’s working.

Should I be concerned?

ingchr1 · Aug 30, 2019

Sounds like the pump may have had air trapped in it.

X-37B · Aug 30, 2019

Anytime you take it out of the water you need to grab the hose and shake the pump up and down a few times. This gets all the air out. Then you should be good to go.

Sleepydoc · Sep 1, 2019

ingchr1 said:
Sounds like the pump may have had air trapped in it.

This.
The Tunze pumps are very prone to air-lock. It’s better if you lay them on their side, but you need to shake them rather vigorously to get the air out.

Huff747 · Sep 2, 2019

Agree with all the above. I tried not to take mine out of the water if possible. When I did clean it I made sure it ran and shook the pump until the air worked its way out.