Smart ATO Micro - Auto Top Off System - AutoAqua

Click on image to zoom
View full size image

More Views

Smart ATO Micro - Auto Top Off System - AutoAqua

74% Recommend this to a friend (14 of 19)

SKU: 209784



1-3 day service on orders over $249

What's this?

Ships Monday

Quick Overview

One of the smallest all inclusive auto top off systems on the market today. The Micro ATO includes an optical water level sensor to keep an eye on the level within the sump with no moving parts. The optical sensor is very reliable, even in complete darkness, keeping a steady water and salinity level replacing any evaporated water with fresh water. The Micro ATO, like its predecessor, uses a magnetic mounting solution that works for tanks and sumps that have up to 1/2" thick walls.

With the possibility of changing the pump for a solenoid valve for direct hook up to a RODI system the Micro ATO can be expanded to run with the big boys.

Note: The mounting location for the Micro ATO sensor will require the ability to see through the wall of the sump or tank. Do not mount in a painted or opaque location as the optical sensor will not be able to see through.


Ask a question

Product Questions

I have a Coralife BioCube 14 which is a 'SUMP-LESS' system. How well will this ATO work for this type setup? If this ATO will work in this situation, would it be best to put the sensor right on the MIN/MAX water level site glass on the side of the tank? If not, where on the aquarium would you recommend mounting the sensor based upon your familiarity with BioCube aquaria?
Thanks for any advice or cautions you might have to offer in response. -R.
Question by: Richard L. on Mar 16, 2016 8:13:00 PM
Great question!
This ATO will require to mount on a section of clear glass for the optical sensor to work. If there is clear glass on the back this may be a great option in the min max level however since the optical eye is on the outside of the tank we do stress that this can only be used on clear glass or acrylic. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Mar 18, 2016 9:21:00 AM
What's the difference between this and the 120p model. I have the original smart ATO and the magnetic side that is inside the sump has rusted. Does this model also have exposed metal?
Question by: Phil Tomaskovic on Jan 5, 2017 3:02:00 PM
Great question! The only difference between the two is that the 120P will include a siphon break. There is not any exposed metal on the wet side of the sensor. :-)
Answer by: Randy (Admin) on Jan 11, 2017 1:09:00 PM
What is the redundancy process for this product? If the sensor fails to shut off the water. For example, the Tunze ATO has an optical sensor and then a float switch for redundancy.
Question by: Mike on Jan 14, 2016 12:51:00 PM
Great question!
The Smart ATO Micro will not have the same redundancy as a Tunze Osmolator. This unit has the optical eye as its only sensor. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Jan 14, 2016 5:00:00 PM
Would the pump fit into the square screw top jugs with a 2 5/16" hole?
Question by: Diane on Jan 14, 2016 3:18:00 PM
Great question!
The pump is just under 2" across and 2 " long. This should be able to fit no problem. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Jan 14, 2016 5:21:00 PM
Literally every other site I see selling this ato clearly states that it can be mounted on opaque AND painted glass, which the original smart ato could not. That was the major selling point for me on the micro. So...can it or can it not? If not, coralvue should have all these other vendors change their product description. Thanks!
Question by: Ryan on Aug 11, 2016 9:50:00 AM
Thanks for reaching out to us! You will need clear glass in order to utilize this product properly. Unfortunately it will not work properly through painted or opaque glass. :-)
Answer by: Randy (Admin) on Aug 15, 2016 7:04:00 PM
What size tubing should I buy to replace the included tubing?
Question by: Keisha Kornbread on May 13, 2016 2:28:00 PM
Great question!
The tubing will be 1/4" Inside diameter 3/8" outside diameter. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on May 18, 2016 12:24:00 PM
Would this be suitable if I add kalkwasser in my ATO tank?
Question by: Douglas Ferrer on Jul 5, 2016 7:53:00 PM
Great question!
This certainly can work as long as the pump does not come in contact with the slurry at the bottom of the ATO container. Keep in mind when pumps are used with Kalkwasser they often do not last as long as with straight RO water. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Jul 7, 2016 9:59:00 AM
What is the difference between this model and the 120p?
Question by: Paul on Jan 26, 2017 6:39:00 PM
Great question! The only difference between the two is that the 120P will include a siphon break.
Answer by: Randy (Admin) on Jan 29, 2017 7:16:00 PM
Can you post a picture showing it set up with a nuvo fusion tank? Question for me - what should I store the freshwater in? Can I drop the pump in a gallon of distilled water?
Question by: TQ on Apr 5, 2016 6:37:00 PM
Great question!
We do not have a photo of the Micro in a Nuvo tank however I have included a link to Coralvue with more details and photos supplied. The pump can be placed in a small container usually a 5 gallon bucket or so with RO/DI water. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Apr 8, 2016 3:11:00 PM
This unit I presume does not have a holder for the hose going back into the tank?
If not what do you suggest to hold the hose
Question by: Bob Escher on Apr 6, 2016 9:22:00 AM
Great question!
I have included a link to the tube holder below! Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Apr 12, 2016 4:22:00 PM
How much must the water level drop in order for the top off to start adding water? Does the pump turn on and off rapidly if there are waves in the tank?
Question by: Mark on Jan 23, 2016 12:58:00 AM
Great question!
This has around 1/4" to 1/3" fluctuation level in the aquarium. The ATO's are designed for no wave environment and will certainly be effected by waves in the tank. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Jan 28, 2016 3:47:00 PM
Can you recommend another check valve that fits the tubing. For some reason mine leaks at the valve provided
Question by: Joseph Lettini on Apr 20, 2016 11:52:00 PM
Great question!
You can use a 1/4" Check valve Kynar fitting
1⁄4” Kynar Check Valve
SKU: 205051
Answer by: Connor (Admin) on Apr 26, 2016 3:07:00 PM
is this unit adequate for a 50-gal cube with a sump?
Question by: Andy D on Feb 18, 2016 7:15:00 AM
Great question!
This will work great with a 50 gallon tank with sump. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Mar 2, 2016 6:30:00 PM

Full Details

An auto top off system is one of the first automated devices any reef keeper should have. When water evaporates, the salt is left behind slowly increasing the salinity of the tank. By utilizing an ATO device evaporated water can easily be replenished by the top off unit throughout the day keeping your tanks salinity very stable. Most of the time the location where the sensors need to be placed can be very limited in space.

AutoAqua has released their Micro ATO system making it the smallest auto top off unit on the market today. The down fall for most top off systems is the float valve or moving parts. AutoAqua utilizes an optical sensor to visually look at the water level. With the magnetic mounting of the optical sensor placement options are limitless while if the magnets are to ever slip or the sensor gets knocked and moved, the Micro ATO provides real-time fail safe protection against such instances.


Whats Included:

  • DC Feed Pump
  • Controller
  • Optical Sensor
  • Power Adapter
  • Magnetic sensor mount
  • Tubing (8.5mm OD - 6.5mm ID)
  • 1 year warranty


Pump Specs:

  • DP-200 Brushless
  • 6.5 ft max head height
  • 74 GPH
  • 4.5w @ 12vDC
  • Cord length 5ft



Items 1 to 12 of 19 total

  1. 1
  2. /
  3. 2
  • Loved it at first, then overfilling my sump...NOT GOOD By slojmn on 2/7/2017

    I did not buy this unit from BRS, I bought it at MACNA. I was super happy with it at first. Then it overfilled which set my skimmer level too high in the sump and the skimmer overflowed. The first time I was surprised but figured it was a fluke. Now it has done it at least 6 or 7 times. It fills a good half inch past the sensor . I'm done with it. Its not worth the headache.
  • ****note there are two modles of this ATO***** By Deva on 1/27/2017

    let me start by saying I did not buy this from BRS wish I had tho...

    so here is the scoop. after receiving my ATO unit and a few hrs of research looks like there is 2 models of this ATO. BRS is the only place I found that show it. but still use the same photographs for both models the pics of the 110P

    SO I thought I would write a review to hopefully help other reefers .

    model SATO-120P has the screw hose cramp system THAT DOES NOT FIT OVER RIMMED TANKS.

    model SATO-110P has the magnet mount system. claiming up to 12mm glass
    all videos demo this unit looks great wish I would have received it.

    so I cant say much about the rest of the unit as I cant even hook it up with out hacking in to my tank. I tested the "universal " hose holder on 10g,20L 29H and 40br tanks. it will not fit over the lip on the inside of the rim.
    its amazing this product even got marketed. WTF

    I did contact coralvue on 1/27/17 about getting a replacement part. i'll keep you posted when and if they get back to me.

    so as of now the ATO is unless unless I want to DIY something.

    hopefully this review will help other reefers understand. I will update my review once I figure this out.

  • Cant trust it! By Ron on 1/18/2017

    ATO keeps failing to refill. It will refill daily for 3 weeks in a row and then one day in doesn't refill. I come home from work and it s beeping, water is below the sensor and it is flashing red. I turn the unit off and back on again and it refills and its good for another couple of weeks. This has happened 6-8 times since I have installed it in Oct 2016. I can't trust this product any longer because of the fail rate.
  • great little product By Matt on 1/6/2017

    This is a great product. I have been using it on my Fusion Lagoon 25 for sometime now. It keeps the water level within 1/8in and is very quite when it is running. I don't know why BRS said's don't use on colored glass, the optical eye is in the tank it does not have to see through anything.
  • Most Reliable ATO I Have Used By Andrew on 10/7/2016

    Easy to setup; sensor is located inside the sump rather than having to pass through the clear acrylic or glass like this company's other non-micro product, which can cause issues if not clean or bubbles interfere; and in six months use, not a single error either overfill or no top off. Highly recommended.
  • Love this ato By Randy on 10/5/2016

    I've had this little guy installed on my 100 gallon mixed reef with 45 gallon sump. I've gotta say "bravo." Such an effective gadget that reduces maintenance time, and such a small footprint in my sump. I'm about to buy another one for a 30 gallon all in one fowlr.
  • Awesomely Small By James H. on 9/6/2016

    I have had this on my Nuvo Fusion 40 for about 2 weeks and it has been working flawlessly. The water level has remained the same and the small pump fits perfectly in a 5 gallon jug. I am limited on space since I do not have a sump and the sensor that is about the size of a penny works perfectly for my situation. The magnets have been strong enough to hold both the sensor and pump hose in place without movement. The only gripe I have is with the siphon breaker that was included. It did nothing but leak so I removed it and since then it has worked like a charm.
  • Does not require clear glass! By Ryan W. on 9/4/2016

    Contrary to what BRS says, clear glass is not required for the micro. It's been setup in my sumpless 25g cube fowlr for almost a month now and has worked flawlessly since day one on painted glass (matte black acrylic craft paint). It only takes about 1/8" of evaporation to kick the pump on and it only runs for 5-9 seconds at a time. Not sure why the refill time fluctuates but my water level remains constant regardless. This is my first ato purchase and I have to say I'm 100% pleased so far.

    The magnet for the sensor is strong enough to push my nerites, of the same size, of it without moving around. And, it still senses the water level when my nerites are on it covering it up.

    Those hose magnet works well too. I drilled a hole in the lid of my AC70 and attached the magnet so the hose was attached to the underside of the lid. Sleek and hidden out of the way. If it weren't for the blue light from the sensor, you wouldn't be able to tell I even have an ato.

    The pump is super tiny. It fits perfectly through the hole in a 2.5g jug of distilled water when you remove the spout from the jug.

    Plenty of cord length for all parts so you can install it virtually anywhere. For a sumpless tank running a hob filter, I can't ask for more. Great product and now I want 2 more for my planted tanks.
  • easy setup and useage By bsco40 on 8/22/2016

    Set up in 10 minutes Do not need to be a rocket scientist to set this up. pay attention to setup of checkvalve the arrow points to the aquarium.

    very easy to use and so far no issues
  • Outstanding By tony on 8/10/2016

    I've been using it for about a month now,and it works great. I use it in my sump and haven't had any issues with it. The pump is small enough to fit in my reservoir and I use it with kalk water. Would definitely recommend this to someone.
  • I loved this item, works great! By Sean on 6/28/2016

    I have had this item up in my tank for a month. it is an office tank that i had to pour water into directly every few days. It was messing with my saliently pretty badly. This item fixed it perfectly!
  • Simple Design, Simple Installation, Maintains Perfect Water Level By Rick on 6/1/2016

    Granted I've only had this unit installed in my Coralife BioCube 14 reef tank for a few weeks but this thing is fantastic so far! Installs in minutes due to simple design, good instructions (diagram) and magnetic mounting. I installed the sensor in the Min / Max sight glass where I can verify the ATO's accuracy as well as see the blue sensor light which assures me that the unit is powered up. Can also see the red light if there is any kind of system alert and the audible alarm can be distinctly heard; not obnoxious, just a good sound level IMO. I use a 1 gallon plastic milk jug as the reservoir which lasts a week very easily in such a small setup. I cut a flap near the top of the jug large enough to allow the pump to be inserted. That flap doubles as the fresh water refill opening. I drilled two holes in the cap through which the pumps power cord and flow tube pass. Voila! Finished. The water level stays exactly where it is supposed to be.

    I can see where algae might grow on the sensor and cause malfunction issues like other reviewers have mentioned; although I have not experienced that problem myself yet. So I just added cleaning the sensor and sight glass to my weekly maintenance schedule as a precautionary measure. Due to the quick magnetic mounting system, a thorough cleaning takes less than 5 minutes literally. I've done it several times now without any problem whatsoever.

    I've had no problem with the magnetic mounting system being too weak for either the fill hose or the sensor. Both seem up to doing the job, at least in the BioCube 14 they do.

    Very glad I purchased this unit and in fact, I haven't found another ATO that would fit properly in the back filter chamber of the BioCube 14 without any physical modifications to the ATO or the BioCube right out of the box.

    Just one minor rap on this product. The anti-siphon device does make a water-tight with the fill tube. It leaks just a bit when pump is activated. I put a zip tie on each end in an effort to stem the leak but unsuccessfully so far. I may have to resort to good ol' mini hose clamps. We'll see.

    Having had an open top 180 gallon reef tank with full sump set-up in the past I can comfortably say that this ATO would have worked very effectively in that setup as well. The only difference is that the fresh water reservoir would obviously have to be upsized dramatically to compensate for much greater evaporation rate.

    A five star rating is well deserved by this product... at least so far. If anything changes in that regard I will probably update this review to reflect longer term experience.