If you prefer reading unbiased product reviews, you may want to skip to the next blog or your favorite reef forum, like Reef2Reef. Because I am here to tell you just how AWESOME the new XP Aqua Sumpless ATO is!

And YES, I am VERY, VERY, biased because it was MY idea. Now, let me show you just how amazing it is and why it is the best ATO, bar none!

Having been a part of the Marine Depot family for years, I have literally spoken to tens-of-thousands of hobbyists and assisted just as many through email. This hobby, sharing knowledge and helping fellow hobbyists, have always been a passion for me.

One of the questions that we are asked time and time again is: “I don’t have a sump. Which ATO should I use?”

This question usually turns in to a long conversation about their aquarium set up; what type of tank they have, whether it has a rim or not, what inhabitants are in the tank and what other equipment they are using. After the conversation, it is then time to go into the database of ATO’s in my head and trying to figure out the best ATO for their application; weighing the positives with the negatives and trying to guess at what would work best and ultimately how happy the customer will be.

There is always a doubt of how well an ATO system will work on a tank without a sump as all current auto top off systems are designed for sump applications.

While chatting with my friends at AutoAqua during MACNA, a light bulb suddenly lit up in my head. All we needed to do was to put a “sump” in the tank, VOILA! We spent hours that night discussing the concept and figuring out what would be needed to make this product a reality.

To make the concept a reality it took extensive conceptualizing, designing, engineering, prototyping, revising and testing. Almost a year later, we are finally ready to present the MOST AWESOME ATO for sump-less aquariums to the community.


The XP Aqua Sumpless ATO is the perfect ATO for just about every aquarium that does not have a sump. At the core of the XP Aqua Sumpless ATO is our new dual-optical sensor. This incredibly small sensor features two optical sensors for precision and protection. Not only is it the smallest sensor on the market, it is also the easiest to install with its magnetic coupling. No more messing with multiple cords, bulky sensor brackets or the hassle of mounting multiple sensors.


The gorgeous in-tank sump that we call the “Flexi” is sleek-looking,  mounts easily with a magnet and can be positioned at any height. We spent months perfecting the design to make sure that the Flexi will complement just about any aquarium from 5 gallons to 90 gallons.

The other benefits of the Flexi are that it is an effective surface skimmer which most sump-less aquariums desperately need.  It also has a handy chamber for housing filtration media such as carbon, GFO or filter floss. We designed the Flexi with usability in mind so it can be easily disassembled and cleaned in seconds.


The Flexi is more than just a housing for your ATO sensors, it's an uber-handy, multi-functioning piece of equipment for your tank that helps you keep a consistent water level, stable salinity and employ filter media all with a single device. We included a tube holder on the Flexi as well so you will have no trouble trying to figure out where to put your ATO return line. Attaching the dual-optical sensor is also remarkably easy as it simply attaches to the Flexi with its built-in magnet. A cord-management clip keeps things nice and tidy.

We wanted to make sure our customers have the best, so we also included an energy-efficient DC water pump that can push up to 8-feet and is guided with a very user-friendly control module.

All parts necessary for installation are included so there is nothing extra you need to buy. Zero programming is required and nothing needs adjusting. All of the XP Aqua sophisticated operation & security protocols have been extensively tested and pre-programmed into the system. The display controller clearly indicates the operating status of the ATO system. The installation can’t get any easier; just plug everything in and you are ready to go!


For a limited time, the XP Aqua ATOs will include the new prototype filter media called the" 1-der Stick" with each ATO so you can be the first to try our revolutionary filter media that is producing excellent results in our test tanks and RD department.

The XP Aqua lineup of Revolutionary Aquarium ATO’s is the most-intelligent, versatile, reliable and attractive ATO to date. When you are so passionate about a project and put so much work into it, it’s difficult to not be biased when it finally comes to fruition and want to shout from the rooftops.