Two osmolator 3 sensors burned out

[Kzang]

So I bought these at end of 2023 and thy stopped working after 6 months. I tried to contact tunze for warranty and didn’t hear anything back. Fast forward today and I finally pulled them out. I’ve been used kalk stirrer for my top off and got rid of my second tank so haven’t needed them. Going to boot up a new tank and well I can’t find a way to call them in the US for support. Email form on their website won’t let me send pics and never heard from them before.

The little nub sensor degraded and let water get into it. The really fried motherboard won’t turn on. The other one with brown burn mark just pumps for a second and then turns red regardless of what you do.

 

[Gumbies R Us]

@rvitko

 

[rvitko Verified Sponsor]

Every product includes all of our contact info in the box

I received your email on Mar 7, you emailed the factory in Germany and they forwarded to me, my reply also dated Mar 7 is below-

Ricky,

Have you tried swapping the power supply with regards to the one with no lights? Can I get photos of the serial number tags that are on the controller cables, sensors with cover removed and a copy of the receipt for each?

Roger

This is an issue that can happen, the safety is a heater, it detects that something is taking away the heat, on the earliest units from 2023 this was much more likely. The design was changed in early 2024 and further quality control steps to check for any cracks in the heater housing were added and it is fairly uncommon on units made after the first quarter of 2024. It can also happen if a 24V power supply is connected by mistake, being a heater, it will get twice as hot, so it is critical to be sure power supplies do not get mixed up.

All I would need is the serial number and copy of the receipt to send a replacement

 

[Kzang]

Every product includes all of our contact info in the box

I received your email on Mar 7, you emailed the factory in Germany and they forwarded to me, my reply also dated Mar 7 is below-

Ricky,

Have you tried swapping the power supply with regards to the one with no lights? Can I get photos of the serial number tags that are on the controller cables, sensors with cover removed and a copy of the receipt for each?

Roger

This is an issue that can happen, the safety is a heater, it detects that something is taking away the heat, on the earliest units from 2023 this was much more likely. The design was changed in early 2024 and further quality control steps to check for any cracks in the heater housing were added and it is fairly uncommon on units made after the first quarter of 2024. It can also happen if a 24V power supply is connected by mistake, being a heater, it will get twice as hot, so it is critical to be sure power supplies do not get mixed up.

All I would need is the serial number and copy of the receipt to send a replacement

I’ll send you a PM

 

[Jarob]

Thata what happened to mine overnight, woke up to a dry sump. Purchased in September 2025 and installed in November so only 5 months of use.

 

[Jarob]

Bumping this because it happened or me AGAIN on my new 2 month old replacement they sent me. This time I wasn't home, I came back from an 11 day trip to my sump dry and 15g still in my ATO. Thank goodness it must have just happened in the last 24 hours. @rvitko

Completely unacceptable for such a high ticket item that our tanks survived off of, and now TWICE...? Beyond disappointed with Tunze and these new Osmolators. These have been on my 220g SPS system

 

[rvitko Verified Sponsor]

I am sorry this happened, unfortunately this failure is possible and if you read the reviews on any ATO, they do fail, all we can do is apologize and we will replace it. When it failed it failed off and did not cause a catastrophic flood (this is the usual failure of most ATO's) and it is electrically safe. I can send another unit, but I need your shipping info and the serial number of this one. We have made a few revisions to solve this and it has gotten less and less likely with each revision. We do have a major revision that will come in the fall, the lens is entirely reworked and much thicker to eliminate this risk virtually entirely. The version you just got, the board was reworked so the safety tripped faster and the lens was hand inspected but this has the possibility of human error. This is not intentional on our side, FWIW, both myself and Felix Tunze have early Alpha models from early 2023 that still function perfectly and we had no advanced knowledge of this before production started and we have worked dilligently to solve it. We had very similar issues for the first couple years with the 3155 and it takes a while to solve every problem with a new product and we do make every effort to solve them before we launch but in some cases we just do not know of a problem until it is in mass production and it can take a few attempts to solve it.