Smart ATO Micro 120P - Auto Top Off System - AutoAqua

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Smart ATO Micro 120P - Auto Top Off System - AutoAqua

64% Recommend this to a friend (7 of 11)

SKU: 210557
In Stock: 131
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Quick Overview

Now Includes Siphon Break

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.


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 tank's 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 downfall 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 ever to slip or the sensor gets knocked and moved, the Micro ATO provides a real-time fail safe protection against such instances.


The siphon break needs to be mounted higher than the water level, and within the ATO reservoir to function properly. Water dripping out the hole when the pump is on is normal.


Whats Included:

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


Pump Specs:

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


11 Items

  • Stuck in on position after one year By Chris on 9/25/2017

    Have had the the auto micro for a little over a year. A month ago the blue light stopped working but it continued to work fine however yesterday a little over a year from purchase it got stuck in on position. Thankfully the 3 times last fill save me from water everywhere. Worked awesome when it worked however would have expected it to work longer than it did.
  • Great product By Kevin on 9/11/2017

    Have have one of these ATO's for my 75 gallon display tank and another on my 200 gallon frag system. One has been in use for over a year the other for six months. Both work as described by the manufacture and I have had no problems with either ATO.
  • Stuck in "on" By Jon on 9/6/2017

    This ATO, after 1 year of use, got stuck in the "on" position. The only thing that saved my floors was the 3x filling fail safe.
  • Pump is garbage By Dirtybirdy on 9/2/2017

    I set up this auto top off unit per the instructions, and after only using it for 6 months, I had already burned through two of the pumps. The manufacturer never replied to my emails. Will never purchase from this company again.
  • Poor product By Fishmankyle on 8/14/2017

    Had the ATO for one year and three months. Now the ATO will not stop pumping, no matter what I do to it. It is pumping water from my storage container even if the water is covering the eye. Worked well when it worked.
  • Not reliable - leaking from Siphon Break By Roman on 6/5/2017

    Not reliable, it started leaking from Siphon Break after 2 month of use. My cabined got all corroded. BulkReef supply is very unhelpful and directed me to the manufacture and told me to work with them. Manufacture is not responding to my phone calls. Very disappointed.
    I'm not going to be buying staff from bulk reef supply anymore.
  • Great By Andres on 4/27/2017

    Worke great love this ato
  • Couldn't be easier. By Michael on 3/30/2017

    I read a lot of nightmare stories before finally jumping in, and I'm really glad I did. Very small, works well, and so far very reliable. Also a much more approachable price than other brands.
  • Little sucker gets it done! By wayfastwhytey on 1/21/2017

    I bought this for my jbj 45rl and it's perfect. The tiny pump has alot of power to pull water almost 6 ft up from floor level.They made this thing idiot proof as well, just plug it in and your set. I would recommend to scoop out some water for the first top off though, because this will be your benchmark setting. The module remembers how long the first top off was and will run 3 min longer than that if need be.
  • Love this little thing! By Imadoggiefosterfailure on 12/15/2016

    I use this on my 180 and it's great! It's tiny, quiet, and accurate. I'm happy!
  • Best ATO for nano tanks By Tony on 12/5/2016

    Just picked this ATO up today and it really so small. And its my option for every nano tank I will ever
    setup. (GREAT PRODUCT)


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Product Questions

Can you tell me how much water line drop this sensor gives you before it triggers the filling command? I want to see if it's more or less sensitive than my current ATO system
Question by: marc on Apr 25, 2017 1:19:00 PM
Hey there,
These ATOs are actually pretty accurate/sensitive to any changes in water level. This ATO uses an optical sensor and a small prism to read the water level and we rarely see more than a small fraction of an inch (perhaps 1/8" to 1/4") before the pump kicks on.

Hope this helps!
Answer by: Zack (Admin) on Apr 28, 2017 10:10:00 AM
Can I put the sensor in a main display tank if I use LED lights? Will LED lights interfere with the sensor ?
Question by: Tom on Apr 29, 2017 9:30:00 PM
Hey there,
You can certainly use this ATO in your display. The sensor uses a small laser and prism and ambient light will not interfere with the unit's function.

Have a great day!
Answer by: Zack (Admin) on May 3, 2017 9:22:00 AM