Why does BRS recommend this?
Bulk Reef Supply tried many different water level switches and auto top off solutions before giving the Tunze 3155 Osmolater Universal Auto Top Off BRS Recommended status. Despite its higher price this is by far our favorite solution. Spending the extra money on a Tunze Osmolater will give you that extra peace of mind and insurance from having a disaster that ruins carpets or hard wood floors. For the value, and reliability it is hard to beat.
Max Head Height: 7.2 ft
The Tunze Osmolator 3155 is one of the safest ATO’s available. It utilizes an electronic eye sensor to monitor water levels and a backup float switch sensor with an optional audible alarm. The controller protects the quiet metering pump from running dry and reports an empty storage tank. Two magnetic holders for sensors and multiple mounting brackets included as well as a pump.
LED indicator lights the Osmolator will allow you to visually see if their are any issues with your top off system.
Two technologies of water level monitoring, and built in safety back-ups.
The optical eye sensor will keep the water level very steady to keep the salinity from fluctuating in your aquarium. The Osmolator does work well with kalkwasser.
Max Head Height: 7.2 ft
Note: With any pump, kalkwasser can cause premature wear. New pumps are available at a very reasonable price.
Easy and low maintenance By GEORGE on 5/9/2018GEORGE would recommend this product to a friendWhile this is expensive, it's worth the process. It has multiple fail-overs, which really make me less concerned about over top off situations. It does exactly what it advertises. It was up and running in >15 minutes and it has an extremely small footprint in the sump, so I could squeeze it in the return chamber easily.
This is not a negative, but some things to consider. The alarm will go off if you are monkeying around in your tank. The high level alarm can be adjusted somewhat, but I have found that it is not enough to make a difference. Also, be careful where you put it in your sump as the high level float valve gets stuck rather easily if anything rest against it (pump cord against it, to close to the sump wall, rogue snail, etc.)
Works as advertised By Mike on 3/29/2018Mike would recommend this product to a friendGreat product, I just wish after it times out filling and the red light comes on that it might just try again, say every 6 hours or so. I like the fact that this is not part of the Neptune system that way if the salinity starts droping my Apex can just shut off power to the auto toper. But just for clarity I have had no issues with the Tunze
Highly Satisfied By Jeremy on 3/18/2018Jeremy would recommend this product to a friendI bought this product from BRS directly because I kmow the quality that they strive for. Out of the box, it was super easy to set up, super to fine-tune to the exact level.
As for other (negative) reviews, most stem from lack of reading directions and/or research. Please understand that no company every makes a 100% flawless product. So, if you experience an issue out of the box or within BRS's warranty limits, give them a call and they will fix it.
Did not work out of the box. Somewhat cheaply put together. By Chris on 3/6/2018Chris wouldn't recommend this product to a friendAfter researching every Ato, I decided to purchase this even though the price was high. I wanted the reliability of a quality product. Out of the box, this product failed. The connection point of the power supply was coated with some kind of white powder and looked caked and corroded. It failed to supply any power to the unit. I'm glad it failed out of the box instead of later. I ordered a new product but received something refurbished. Tunze was not as high quality as I expected.
dependable By Scott Sheperd on 2/7/2018Scott Sheperd would recommend this product to a friendI use this mostly for going on vacation. Tank loses 1-2 L / day depending on relative humidity. I use a 5 Gal bucket as a reservoir for the pump.
Pump is essentially silent, runs for 10 seconds beyond perceived fill height to reduce the number of starts/stops.
PERFECT By PETER on 2/2/2018PETER would recommend this product to a friendHAVE THEM ON BOTH OF MY TANKS. I CAN'T BE HAPPIER WITH IT
Quit waiting and buy this ATO! By LandLockedReefer on 1/15/2018LandLockedReefer would recommend this product to a friendSuper reliable and accurate. The optical eye prevents the quick cycle times cause by a normal float switch. Make sure to clean the sensor before use and keep it clean. I have had this for 6+ months and have had zero issues. The magnet is very strong and will not move once set in place. It makes some noise but not ridiculous. If there is excessive noise, air may be trapped next to the impeller so shake the pump some to get the bubbles out. Much better than hauling buckets around to fill the tank.
Reduce Daily Maintenance and Improve Stability By Justin on 1/14/2018Justin would recommend this product to a friendBased on BRS videos and reading reviews, it seemed like a no brainer that the Tunze Osmolator 3155 is the best choice for ATO. Before I set it up, I would have to add RO/DI water to my sump daily which didn’t take more than a minute or two but did add to the daily tasks necessary to keep a reef tank. Also, the swings in salinity were probably not the best for the tank inhabitants. I installed the Tunze ATO and could not be more satisfied as it has kept the water level exactly where it needs to be and all I have to do is top of the ATO water bucket once a week.
The only concern I had was when I performed a water change, I unplugged the ATO system and once the water change was complete the water in the sump was several inches above the water line, I plugged back in the ATO system to see if the sensor would indicate the water level was too high. However, the reading indicated the water level was to low and started pumping RO/DI into the sump. I unplugged and removed the excess water from the sump to get it to the correct water level. Once I plugged in the ATO again, it read the water level correctly and has worked as expected since. It is something I will keep an eye on with future with water changes but based on how it has performed to date, I would highly recommend it to anyone looking for an ATO.
Does its job but needs a couple upgrades By Cali on 11/29/2017Cali would recommend this product to a friendI have had this unit for 8-10 months and have just recently began having issues with it. I was getting a water damage error...... but this thing is no where near any water. Himidity buildup in the brain is enough to cause the unit to stop unit. I got the hair dryer out a few seperate times before just leaving the back cover off to allow air flow. There is no reason that these electronics cannot be epoxy filled in order to be waterproof. Everything in this hobby is marked up to a premium but are missing the small features like this for durability. Come black friday i could not decide between another tunze or the atk. Time will tell
Super Reliable By John on 11/28/2017John would recommend this product to a friendI've had one of these running on my tank for over a year. Works wonderfully, without any issues at all. Great time saver. I love the built-in redundancy (never needed it, but peace of mind). I just installed a 2nd one for another tank build.
Easy By AbominableBro on 11/27/2017AbominableBro would recommend this product to a friendA must have for all aquariums.
The best long term ATO By Eddie on 10/25/2017Eddie would recommend this product to a friendI have owned a couple of Tunze and a Neptune. Neptune is little more finicky with the water level and the very hardly audible alarm. The Tunze Has been a better product long term. The Tunze does not have that huge plate and float ball of the Neptune. Tunze very heavy duty with very strong magnets. Always make sure your output is above the level of the reservoir or place the hose in a camouflage PVC.
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?
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.
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
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.
How much head will the pump push
The pump on the osmolator has a max head height of 7ft.
Hi, by head pressure does this mean how many feet the pump will push the water? So if my pump is in my cabinet under my tank will it push the water to the top of my tank? Thank all over at brs..
Head pressure is the maximum height that the pump can push water vertically. If your tank is higher than the Head height listed this will not be able to work. Feel free to let us know if you have any further questions!
You say additional switch socket adapter to handle more head pressure. Where can i find this? I traveling about 15 feet 9 of that is up.
Will the sensor fit in the sump of an innovative marine 30L ?
This will work great in the back of a nuvo 30! Feel free to let us know if you have any further questions!
What is the measurement on the pump, as in the widest part? I need to know if it will fit in my container I plan to buy.
The diameter of the pump is just under 2" this is how wide the cap will need to be in order to allow the pump to pass through.
Is the retaining magnet waterproof?
What are the dimensions of the blue Tunze controller module/box. I am trying to determine if this will fit on an existing mounting board. Also, how does it mount? Adhesive or punchouts in the back plate. I don't see screw holes like the Apex modules have. Thank you.
This will be 4" long, 2.5" wide and 1" thick. it will require a Velcro pad to stick or to be used with double sided tape.
I have a 10 gallon tank and am concerned with salinity swings. I top off my tank every day but I'm afraid most of these ATO would not fill the evaporated water before my salinity starts to rise. What is distance vertically from the low to full position?
The optical eye sensor will usually sense and fill within the range of 1/4" Feel free to let us know if you have any further questions!
I have turned the control up to the max however it will not keep up with the evaporation? my tank is a 120 gal with 35 gal sump.
If you have calibrated the pump to maximum output and it is still unable to keep up you will want to ensure the pump is filling the proper amount. It may be that the head height (the vertical height the pump has to push the water) could be too high or other pump related problems. We have used the osmolator on larger systems with quite heavy evaporation with great luck. If the issues continue you will want to contact Tunze directly to see if the pump is working correctly! I have included their contact information below!
Tunze – 512-833-7546 email@example.com
Will this work with the Apex controller?
The Tunze Osmolator is an entirely self sufficient system. It is perfectly fine to connect the Osmolator to one of the Apex's power outlets incase you wanted to cut the power for some reason (like when you are doing a water change) though the Apex isn't capable of reading the Osmolator's sensors or anything of that sort.
Hello. I bought a used Tunze osmolator today. Do you sell replacement parts, such as the magnetic sensor holder. And, what is the best way to clean the sensors? Thank you. :)
Could you please post or email me, what differs from the 3152 and the 3155?
The 3155 will have 2 sensors the mechanical float and the optical eye. The 3152 will only come with the mechanical float switch. Feel free to let us know if you have any further questions!
Can you tell me the diameter of the wet side unit? I need to make sure it will fit inside the return pump side of my bio cube 14. I’m worried the sensor will not fit due to the narrow area I have to work with.
I have the -osmolator nano 3152 ATO and I was wondering the water level controller can be adapted to it
Would you happen to know the max head pressure of the Tunze Osmolator's pump?
The max head pressure on the osmolator pump is 7ft.
I purchased the osmolator from your site and was under the impression it had an alarm that went off if the ATO container was empty to prevent the pump from burning up. I've tested this, but my pump just keeps running and there is no alarm?
This osmolator will run for typically 10-15 minutes in a dry container. eventually the controller will sense that it has not filled in a timely manner and should turn the system off. if this continues to not be filled there may be red flashing on the controller. For direct assistance you will want to contact Tunze directly!
What is the power consumption of this unit?
The power supply has 12V, 1600mA maximum output, connected to a watt meter with the pump running, the draw at the outlet is generally around 8W at 115V with the pump running. The entire system uses 1-1.5A at 12V depending on pump speed setting and head pressure.
What pump do you suggest to go with the3155 osmolator?
The Osmolator actually comes with the pump right in the package so you don't need to buy one!
Can i purchase this item with a australia (SAA3) wall pug not a north america one thats shown in the photo?
We appreciate your interest, but I'm afraid our distribution area is limited to North America and all of our equipment is wired for standard US 110v electrical.
Have a great day!
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.
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.
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?
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
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.
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).