XP Aqua Ultimate ATO The Ultimate ATO is the world's first auto top-off system with 4 optical sensors.

At XP Aqua, we set out to create the Ultimate ATO: an auto top-off system that offers the ultimate protection, ultimate precision, ultimate versatility, ultimate convenience, and the ultimate value! We believe we've accomplished this by building the aquarium industry's first 4-sensor auto top-off system.

  • Sensor 1 for top-off detection
  • Sensor 2 for over-fill protection
  • Sensor 3 for dual over-fill protection
  • Sensor 4 for run-dry protection (an industry first)

XP Aqua Ultimate ATO The two dual-sensors come pre-installed inside a handsome magnetic sensor holder.

More Protection

We've developed the first and only auto top-off system with real-time under-fill protection. Gone are the days of discovering that your return pump has been running dry or your ATO hasn't been topping off for days.

XP Aqua Ultimate ATO

Ultimate Precision

Ultimate ATO XP Aqua A Closer Look

The Ultimate ATO features a precise optical sensor for dedicated under-fill detection. It will sound the alarm the instant it detects a problem. In addition to being the only auto top-off with a sensor dedicated to under-fill protection, the Ultimate ATO has two sensors dedicated to over-fill protection. The lower over-fill sensor triggers a soft audible alarm and the higher sensor triggers a louder alarm which lets you know your aquarium requires immediate attention.

XP Aqua optical sensors are best in class. The company does not use float switches which can stick. We do not use float valves which are prone to leaking or getting jammed with salt creep. Optical sensors are superior technology. We believe that every layer of protection deserves the best security we can offer. We've made no compromises in building the Ultimate ATO so that you can have peace of mind that your livestock and equipment are safe.

XP Aqua Ultimate ATO For larger aquariums, the two dual optical sensors can be removed from their holder and installed separately.

Ultimate Versatility

When we conceived of the Ultimate ATO, we wanted to make sure it could be adapted to many different aquarium systems. The two dual-sensors come pre-installed inside a handsome magnetic sensor holder. In large aquarium systems where sump water levels may change dramatically, the two dual-sensors can be removed from the magnetic holder and installed separately. A cool Easter egg feature you might get use out of is putting one sensor inside your sump and the other in your ATO reservoir for run-dry protection (if you are using the AC switch with a larger ATO pump). We have you covered!

XP Aqua Ultimate ATO Plug and Play: The XP Aqua Ultimate ATO is ready to go right out of the box!

Ultimate Convenience

We wanted to make installation as easy as possible. No programming is required. There are no settings to adjust. Just plug it in. That's it! You are ready to go right out of the box. All of the sophisticated logic I've described are pre-programmed to work for you the first time you turn it on.

XP Aqua Ultimate ATO The Ultimate ATO includes everything you need and more.

Ultimate Value

The Ultimate ATO includes a DC (Direct Current) ATO pump, an AC (Alternating Current) switch, and a RO (reverse osmosis) solenoid switch. The included ATO pump can pump water up to a height of 8 feet. The pump operates at a safe voltage of 12V.

The AC switch is perfect for bigger aquarium systems or in situations where the ATO reservoir is located remotely. Simply plug in your pump of choice (up to 10A/1,000W) to the AC switch and you are good to go! The RO solenoid is great for those topping off directly from a RO/DI (reverse osmosis/deionization) system. There are no expensive accessories you need to buy. You do not have to worry about compatibility.

Made With ? By Real Aquarium Hobbyists

XP Aqua was founded by passionate aquarium hobbyists. We set out to create a solution we could be really proud of. A product that excited us and that we would use ourselves. We spent almost a year designing, developing, and extensively testing this auto top-off system. We hope you'll love the Ultimate ATO as much as we do!

If you enjoyed this article by Joseph Chang, check out his other recent contribution to the Marine Depot Blog about XP Aqua's Sumpless ATO: the first auto top-off built specifically for tanks with out sumps!