Auto Top Off for Saltwater Aquarium Water ATO System for Both Reef and Fresh Tank – Blue
Original price was: $49.99.$39.99Current price is: $39.99.





Price: $49.99 - $39.99
(as of Oct 17, 2025 02:55:11 UTC – Details)
Product description

All aquariums experience regular water evaporation. As the water evaporates, the aquarium’s water level decreases, leading to an increase in salinity concentration, which can negatively impact your aquatic life. Manually adding fresh water is a tiresome yet crucial daily chore. Useek Auto top off systems automate this bothersome task, saving you time. ATO not only help maintain a consistent water level but also a stable salinity level, keeping your tank inhabitants content and healthy. Set off on a vacation with peace of mind, knowing your water levels are well managed!

Smart ATO is an automatic water replenishment system suitable for aquariums of any size. It combines ATO level sensors with fault safety sensors and integrates Quick Safety Technology (QST), providing real-time protection against any malfunction and detecting empty reservoirs.Smart ATO offers you a safe and stable automatic water replenishment option!

LED Indicators:
Red and Blue Alternating Flicker: Your device is currently booting up.
Blue LED:
Solid blue LED: Standby mode.Slow flashing blue LED: Refilling water/starting water pumpRapid flashing in a brief period: Water level has reached the HIGH sensor; anti-overfilling feature is activated.
Red LED Flicker:
1. Bubbling interference is present 2.Water tank is low on water.You need to clean the probe or move the sensor to a bubble-free area, or add water to the water storage tank.

ATO Sensor precision: 1mm
Power supply: AC 100-240V/50-60 Hz input, DC 12V/1A output.
Power cord length: 6 feet
Pump flow rate: 74 gallons/hour (270 liters/hour)
Pump cord length: 6 feet
Installation thickness: 15mm
Tubing: 6 feet, inner diameter 7mm

Package Dimensions : 6.46 x 6.34 x 2.68 inches; 14.07 ounces
Item model number : AT-200
Date First Available : May 15, 2023
Manufacturer : Useek
ASIN : B0CFVWDKMC
Best Sellers Rank: #10,453 in Pet Supplies (See Top 100 in Pet Supplies) #14 in Aquarium Water Pumps
Customer Reviews: 4.0 4.0 out of 5 stars 526 ratings var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });
WHY YOU NEED ATO? – All Aquarium regularly evaporate water. In salt water Aquarium, as the water evaporates, the water level in Aquarium will drop and the salinity concentration will rise. Compared with other methods,The ATO system automatically maintains the water level in the aquarium, preventing fluctuations in salinity concentration and maintaining a stable and healthy environment for aquatic life.
SPACE-SAVING, COMPACT DESIGN – With a nano size of only 0.7 inches diameter, this Auto Top Off for aquariums is both unobtrusive and elegant, fitting seamlessly in rimmed or rimless tanks and sumps.
REAL-TIME PROTECTION WITH QST – Our ATO system carefully calculates and adjusts to the ideal fill time, offering visual alerts and stopping the pump if it detects a refilling time 6 times longer than expected, ensuring protection against overfilling, dry running, and sensor malfunctions.
EASY INSTALLATION & VERSATILE USE – The Auto Top Off kit includes everything you need for a hassle-free setup, making it simple to integrate into any rimmed or rimless aquarium. A perfect gift for aquarium enthusiasts, this system is a delightful surprise for friends and family alike.
TWO-YEAR WARRANTY & RESPONSIVE CUSTOMER SERVICE – Your satisfaction is our priority, so we offer a two-year product warranty and friendly customer support to address any questions or concerns. Enjoy peace of mind with our free replacement policy and helpful assistance.
Customers say
Customers find the ATO system easy to set up and appreciate its build quality and value for money. The device effectively maintains proper water levels, and one customer notes it’s super quiet. However, the functionality and pump efficiency receive mixed reviews – while some say it works great, others report it stops working and the pump fails. Additionally, the lifespan is concerning, with some units lasting only 9 months. The noise level also gets mixed feedback, with some finding it quiet while others say it’s a little noisy.
13 reviews for Auto Top Off for Saltwater Aquarium Water ATO System for Both Reef and Fresh Tank – Blue
Add a review
Original price was: $49.99.$39.99Current price is: $39.99.
Andrew H. –
Great Aquarium tank water level maintenance system!
This auto top-off aquarium system is a gamechanger. It is sooo easy to install and increases my tank quality with maintaining the water level. Itâs very quiet and low maintenance. Very affordable, high quality and does everything I need it to do.
Ronny Acosta –
Should have purchased sooner
I’ve had this saltwater tank for awhile and I should have purchased this auto top off so much sooner. This unit really has made maintaining my fish tank so much easier. The size of this is less than an inch and it doesn’t stick out in my tank either. It fit perfectly on the rimless setup without taking up a lot of space. Setup was super easy and everything I needed to get this running came in the box. Overall, it took me about 15-20 to have this setup and ready to use. I really like the safety feature it has that monitors and refills my tank with an auto shut off. I have left my house for the weekend and came back to absolutely no mess but my tank maintained its level of water. Plus, once its attached to my tank, it doesn’t fall off either, very sturdy. Plus the other thing I noticed is that this whole thing doesn’t make any noise. All I hear is running water every now and then and that’s it. There have been no sudden swings of stressing my fish out either.
Tom Wahl –
Need something temporary? This may be your answer!
a 30-day replacement policy seems appropriate. I purchased on February 15 and had it up and running probably a week after it arrived. Easy set up, and it works. A little noisy, but not horribly. Now it’s the first week of May and it no longer works. Sensor seems to be dead, for all I know the pump is still OK but there’s no way to tell. So I got a little over 3 months out of it and now I have to find something else.
Lindsey Jones –
Works! Great purchase
This ATO is simple to setup and is very easy to use. Itâs super quiet and even works with a smart plug! The magnet is very strong too. Great quality. Built to last. Highly recommended to keep your tank full!
Doesnât work, keeps filling, flooded my floor with water and made my salinity drop –
At first didnât work but now it does
Although at first it flooded my floor twice, and dropped my salinity, I have it a third chance and now is working like a charm, dunno what changed
Regena –
Easy to install
Reliable and easy to install, the Useek ATO system keeps my saltwater tank topped off effortlessly. Great for reef and fresh setups. Solid performance with minimal maintenanceâworth it for peace of mind.
Kyle –
Ok for the price. Don’t expect it to last too long.
I don’t want to completely diminish this product. It’s not hard to assemble or use. It’s small and indiscreet if you can cover the light of the sensor. For the price you pay it’s decent.I do worry that the sensor maybe isn’t as water proof as it needs to be. It will likely stop working before a year. I have purchased two. One is still going the other has a solid red light when powered on and in place and will no longer operate. I have tried using both distilled water and 99% alcohol to clean the sensor and it has not worked. I even soaked the sensor in alcohol overnight. The only other thing I can think to try is maybe cleaning the pump. I’m pretty certain it is finished though. If you can, try to place the unit and disturb it as little as possible. I think when I removed it recently and let it dry that was what ultimately did it in.Simple set up and mechanism. Decent price and design. Poor longevity.
Christian A –
Works well
Lasted me a good 3 years just recently the motor gave out But Iâm partly to blame since I had run the motor dry a couple of times. Just bought again to replace the parts. Does the job well
Marie-Pierre Landry –
Je suis revenu de vacances pour mâaperçevoir quâil faisait un bruit horrible et que le moteur de la pompe à eau nâarrivait plus à pousser lâeau dans le tuyau vers lâaquarium. Argent gaspillé et faillit tuer tous mes poissons dâeau salée.
Albin Lover –
Ha funcionado muy bien
Roberto –
Excelente producto muy buena precisión y fácil de instalar
Uriel Mancilla Basilio –
Muy bueno el producto comple perfectamente con lo especificado
Toni –
I purchased this product to only use while on vacation. I didn’t trust it for everyday use and could manage to top off my reef when working from home. I took one 3 week trip and came back to an awful grinding sound from this device. I’m unsure when this malfunctioned, but it’s safe to say it’s unreliable and likely just unsuitable for a saltwater tank.