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Very Cool! By Trent on 12/16/2014Trent would recommend this product to a friendThis is a great product. Easy to setup and trouble free.
One funny thing is that the way that the LED indicator lights are mounted inside the control box allows for "bleed over" from one light to another. So, in my particular case, the way that I have it mounted inside my cabinet makes the "Too High" appear to be lit when in fact it's the "Level" light. It took me a couple of plug-unplug cycles to figure that out.
But, it's great product. Recommended!
Still the best! By Martin on 12/15/2014Martin would recommend this product to a friendThere have been a lot of additions to the ATO market over the last year or so. The Tunze 3155 Osmolator is stil the best unit on the market. Reliable and dependable. If you're undecided because of price, don't be...just buy it and be glad you did.
Works flawlessly By GARY on 12/15/2014GARY would recommend this product to a friendBought one thanks to the positive reviews here and I owe the reviewers here a debt for getting it right and saving Me Money making a mistake.
Want an ATO, click 'ADD TO CART' on this and be done with it.
great product By kalen on 12/11/2014kalen would recommend this product to a friendI recently bought the tunze ato and I had heard many good things about it. I did many months of research and I finally decided to buy it and replace my smart ato which was always failing. I would recommend this product to others
Tunze osmolator 3155 Top Off By Joe on 12/10/2014Joe would recommend this product to a friendThis is the best automatic top off system I have 3 of them on different tanks. Easy to set up plug and play. They been running for over 3 years with no problems.
The best By John g on 12/9/2014John g would recommend this product to a friendVery easy to set up and extremely accurate
Easy Setup By Evelio on 12/9/2014Evelio would recommend this product to a friendIt was easy to set up straight out of the box. This is one of the best investments that I have made for my tank.
ONE WORD....WOW!!! By NASSAUREEF on 12/8/2014NASSAUREEF would recommend this product to a friendThis top off is amazing very easy to setup. Don't waste your money on another brand cause it will cost you double and you will end up with the tunze , so buy it the 1st time and it will be the last one you will buy..
Simply perfect By Nate on 12/8/2014Nate would recommend this product to a friendI have used two tunzes osmolators on different tanks and I have never had an issue. double back up (float sensor and auto times pump shut off) makes me not worrying about having water over flow. and all the install hardware added is always a bonus, like the return tube holder.
best investment i made By Andre on 12/6/2014Andre would recommend this product to a friendMy first ato and only I will buy. very happy with this ato. Easy to install
Love it! By Joshua on 12/5/2014Joshua would recommend this product to a friendI have had a few different ATOs but this one is by far the best I have had. Don't know why I didn't just get this one from the start.
GREATTTTTTTTTTTTTT By TOM on 11/29/2014TOM would recommend this product to a friendJust got this auto off was really easy to install took about 30 mins and WOW... this system is great would recommend this to everyone. I was waiting for the sale Blackfriday what a great deal...
Previously Asked Questions
by Daire Fontaine on January 17, 2014, @12:23 AM
My Tunze Osmolator ATO keeps getting stuck in the ON position. I soaked the electronic eye in vinegar and it was fine for a week, but then it stuck on again. Do these electronic eyes fail after many years of use? I've been using it for about 4 years. Is there any way to replace the eye without having to buy a whole new system?
Bulk Reef Supply Hi Daire,
We run into very few issues with these but after that length of time I would imagine its possible for any component to fail. We don't have individual parts like the optical eye, but if you give Roger and company a shout over at Tunze USA, he might. At the very least he could likely help you narrow down exactly what it is. The number I have for them is 512-833-7546 firstname.lastname@example.org
by David on May 10, 2014, @11:50 PM
Would you happen to know the max head pressure of the Tunze Osmolator's pump?
Bulk Reef Supply Hi David,
The max head pressure on the osmolator pump is 7ft.
by Mark on June 5, 2014, @8:39 AM
Does the pump get placed directly in the top off water reservoir? If so what are the dimensions of that pump? I am trying to decide what kind of reservoir I can use before purchasing a ATO.
Bulk Reef Supply Hey Mark,
That is correct. Its a submersible pump that gets stuck right into the top off water. If your interested in this ATO system you should give this blog article a quick read. It goes into a lot more detail on the system (which is one of my favorites).
by Jeff on November 28, 2013, @2:50 PM
How much head will the pump push
Bulk Reef Supply Hey Jeff,
The pump on the osmolator has a max head height of 7ft.
by BILL on November 13, 2013, @7:37 AM
what pump do you suggest to go with the3155 osmolator?
Bulk Reef Supply Hey Bill,
The Osmolator actually comes with the pump right in the package so you don't need to buy one!
by Christian on July 17, 2014, @9:40 PM
If i have a wave maker and this ATO in the same tank (I don't have a sump), would the waves cause the pump to turn on and off constantly? Thanks
Bulk Reef Supply Hi Christian,
In theory it could present a problem but the circuitry in the Osmolator should help to prevent that. Every time the ATO is triggered it runs for a minimum of 15 seconds. It adds overfill to prevent short cycling. In most cases this should be sufficient unless the height of your waves is constantly changing.
by Spencer on April 29, 2014, @12:54 PM
I have a litermeter 3 that has failed. It pushes water about 30 feet from the litermeter to a sump tank. Will this pump do the same?
Bulk Reef Supply Hi Spencer,
The max head pressure on the included pump is about 7ft. It likely wouldn't be well suited to this application. That said though, you can get the additional switch socket adapter which would allow you to control any pump via the osmolator system. That way you can use a pump that can handle the head pressure.
by Ronald on January 13, 2014, @2:32 AM
Just wondering if I need 2 ATO. I know you can place it either in the sump or in the tank, but my question is if I place it in the sump will it also refill my tank in that process. I don't see that happening but if it does please let me know.
Bulk Reef Supply Hi Ronald,
If you have a sump, it MUST go in the sump, in the chamber where your return pump is. This is the only area of your tank that will have a changing water level depending on evaporation (unless its far too late!). Only one ATO would be necessary but it must go in that location if you have a sump.
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