FZONE ATO with Controller, QST2.0 Auto Top Off System for Saltwater Aquarium & Freshwater Aquarium

I’ve been using the FZONE ATO with QST2.0 Controller for a few months, which has completely streamlined my tank maintenance routine. Right out of the box, I was impressed by the build quality — sturdy components, well-packaged, and clear instructions. Setup was a breeze. It took under 20 minutes to install and calibrate everything.The QST2.0 controller is the real star here. It’s smart, responsive, and offers a level of precision that gives me total peace of mind. The sensor is extremely accurate and doesn’t require constant tweaking like some cheaper models I’ve used in the past. I particularly appreciate the fail-safe features — if something goes wrong (like the reservoir running dry), the system alerts you and shuts off automatically to prevent any disasters.I’ve noticed a significant improvement in the stability of my tank's salinity and water levels since installing this ATO. It's super quiet during operation, and the included tubing and bracket are both high quality and easy to position just right.I had an issue months later with the sensor accuracy, contacted Customer Service and they replace the part immediately! Thanks Cheryl!If you're on the fence, don't hesitate — the FZONE is worth every penny.Highly recommend!

This ato is very easy to set up. It should be stated in the description of the product that it is designed for a rimless tank. My tank had to ram around it, so I had to trim some of the rim four, the optic, and the clamp that holds the hose that feeds the water two, we're correctly. If you're handy it's no problem. Time will tell as far as reliability and quality of build. I have a seventy five gallon tank. I use a five gallon reservoir. With that, and the set height of the water in the tank, if it was to ever overfill, the entire five gallons would go into the tank without overflowing as a fail safe.

Stoped working 32 days after buying. Buyer beware bad product!

I live in a hot climate city, and I originally bought this ATO to prevent water levels dropping too much from evaporation while I was on extended vacation. The ATO met exactly this purpose, thus allowing stability with my planted tank (CO2, lighting, and filter flow staying stable and preventing algae) and keeping the fish happy.I originally planned to only use it when I am away for extended periods, since I was concerned with the appearance of an extra device and tubing, however I am able to keep it quite discretely tucked in the back corner and it does not detract from my tank viewing. Having kept it installed, I no longer need to manually top off my tank with buckets, but rather less frequently refill the bucket with pump that I keep in my tank stand's cupboard.An additional way I've been using the ATO is for adding back water after a water change. It is simple to pause the device when removing water, and resuming to pump new water back in until the water level. Knowing it will automatically stop at the appropriate level gives peace of mind when I need to walk away.For peace of mind, I do have the ATO connected to a smart plug that I can shut off through my phone. I have always kept smart water leak sensors that give real-time alerts to my phone, so I can disable my filter and now ATO in case there was any instance of leaking from any failure points in my tank.I've been using an FZone CO2 regulator for a few years now which has been completely reliable, and am equally happy with their ATO as well!

This FZone auto top off system is fantastic. It arrives in a branded box with the ATO system well laid out right when you open it. Under that tray is the power connector as well as a length of tubing, manual, and some suction cups and accessories to hold the hoses and pieces in place.The auto top off system works by placing the sensor in the tank with the middle of the sensor at the desired water level you want to keep the water at. When the water drops below the middle, it begins to automatically fill up via the included pump. There are various LED indicator status which is described further in the manual to tell you if anything is wrong.One of the best features is that you can press the button to pause and resume filling, so that means I can pause it, do a water change and take out any water I need to, then press resume for it to automatically fill the tank back up.Overall, this is a fantastic system that is very reliable so far compared to others that I have tried. The included pause/resume function on this is also a major plus for me as I like to do water changes and don't want to unplug the entire ATO system and redo it every time.

The only problem I have with this is, sometimes the motor doesn't work and it's a pain to get it started again. But 99% of the time it works just fine and I would trust it if I had to leave for a week

I've been using this ATO for several months now and it's working perfectly. The included controller is a huge plus because you can 'pause' the ATO when you're doing water changes or turning off pumps and the water level temporarily changes.The LED light on the controller is pretty bright but I solved that by putting it inside a protective power strip box.Wipe off the sensor when you're doing water changes to ensure a long service life.

5/9/25 - I’ve been contacted by the seller and offered to review the updated unit to see if it resolves my issue. Customer service appears to be excellent. Will report back on experience. Moving to 3 stars during review.I wanted to love these and was so excited that I found ATOs for a third of what they charge at the fish store. I have three of these and have never once made it past 8hrs without them alarming and shutting off. Complete waste of money and now I get to go spend all the money I was trying to save.