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

Click on image to zoom
View full size image

More Views

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

100% Recommend this to a friend (4 of 4)

SKU: 210557
Please wait...


1-3 day service on orders over $249

What's this?

You could earn
620 points
($6.20 off a future purchase!)
Ships today
order in
4h 32m

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.


Ask a question

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

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


There are no videos related to this product.


4 Items

  • 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)