XP Aqua Sumpless ATO2

XP Aqua Sumpless ATO2 is a complete automatic top-off and surface-skimming system designed specifically for aquariums without sumps. It combines XP Aqua's dual-optical sensor ATO with a magnetic Flexi overflow box, surface skimmer, media chamber, ATO pump, and reversible DC pump to help stabilize water level while improving surface clarity.

XP Aqua Sumpless ATO2 for Aquariums Without Sumps

Most automatic top-off systems work best in a stable sump chamber, but many aquariums do not have a sump. The Sumpless ATO2 solves that problem by using a dedicated overflow box inside the display aquarium. As evaporation lowers the level in the box, the dual-optical sensor ATO replaces freshwater from the reservoir while the overflow box also helps skim oily surface film.

Sumpless ATO and Surface Skimmer Features

• Designed for sumpless aquariums: Built for display tanks and aquarium setups that do not have a traditional sump chamber.
• Dual-optical sensor ATO: Uses XP Aqua's compact dual optical sensor for precise water-level control with a secondary failsafe.
• Intelligent pre-programmed control: Built-in controller programming helps protect against overfilling without user programming.
• Surface-skimming overflow box: The Flexi overflow box helps remove oily surface film and improve gas exchange.
• Integrated media chamber: The overflow box can also hold suitable filtration media such as carbon, GFO, or other media chosen for the aquarium.
• Plug-and-play design: All core operating parts are included for a complete sumpless ATO installation.
• Works in complete darkness: Optical sensor operation does not depend on aquarium light.
• Magnetic mounting: Sensor and overflow components mount cleanly on suitable aquarium glass.

Sumpless ATO2 Pump and Overflow Specifications

• Product type: Sumpless automatic top-off system with surface skimmer and media chamber
• Application: Freshwater, saltwater, reef, and display aquariums without sumps
• Power input: 100-240 VAC, 50-60 Hz
• ATO DC pump head: 8.2 ft / 250 cm
• ATO DC pump flow rate: 74 gph / 280 lph
• Flexi reversible DC pump head: 6.5 ft / 200 cm
• Flexi reversible DC pump flow rate: 74 gph / 280 lph
• Flexi overflow box dimensions: 3.94" x 2.17" x 6.30" / 100 x 55 x 160 mm
• Maximum media chamber volume: 3.74" x 1.99" x 1.97" / 95 x 50.5 x 50 mm
• 1-der Stick Ultra Media dimensions listed by J&L: 3.54" x 1.5" x 1.89" / 90 x 38 x 48 mm
• Maximum mounting thickness: 1/2" / 12.7 mm
• Freshwater reservoir: Sold separately

Sumpless Aquarium Planning Notes

• Best application: Aquariums without sumps that still need automatic freshwater replacement and surface-film control.
• Surface level planning: The Flexi overflow box must be mounted at the correct display water level so it can skim the surface and let the ATO sensor read properly.
• Media chamber use: Use only appropriate aquarium filtration media and avoid packing the chamber so tightly that flow becomes restricted.
• Reservoir safety: Use a clean freshwater reservoir and route tubing so it cannot siphon or dump uncontrolled freshwater into the aquarium.
• Maintenance access: Mount the overflow box where the media chamber, pumps, and sensors can be inspected and cleaned easily.
• Sensor reliability: Keep the sensor area free of algae, trapped bubbles, salt creep, and debris.

XP Aqua Sumpless ATO2 Setup Directions

1. Choose a display-tank location with enough clearance for the Flexi overflow box, magnets, tubing, and pump cables.
2. Mount the Flexi overflow box on clean aquarium glass within the supported 1/2" thickness range.
3. Install the dual optical sensor in the overflow box according to the XP Aqua instructions.
4. Place the ATO pump in a clean freshwater reservoir and route the top-off line securely to the system.
5. Install the Flexi reversible DC pump and confirm water is moving correctly through the overflow box and media chamber.
6. Add the included media or other suitable media without overpacking the chamber.
7. Check that the outlet tubing cannot siphon freshwater after the ATO pump turns off.
8. Power the system and run several test cycles before relying on it unattended.
9. Clean the overflow box slots, media chamber, sensor, and pumps regularly to maintain stable operation.

What's Included

• XP Aqua Sumpless ATO2 controller with dual-optical sensor
• Flexi overflow box with magnetic mount
• ATO DC pump
• Flexi reversible DC pump
• Power adapter
• Top-off tubing and installation accessories
• 1-der Stick Ultra Media