Prism ATO

(22 customer reviews)


The Reef Breeders Prism-ATO is super compact and has 3 sensors. It works great for maintaining your water level in tanks small and large.

1893 in stock (can be backordered)

Warranty Period

SKU: ATO-PRISM Category:


The Reef Breeders Prism-ATO  is designed to work with aquariums of all sizes, from pico desktops and All-in-One aquariums with limited space, to large reef tanks with full sumps. The Prism ATO has 3 sensors and registers your water level in a fraction of a second. It’s small platform allows it to be installed unobtrusively almost anywhere!

Fully Self-Contained.

The Reef Breeders Prism-ATO is fully self-contained, meaning the controller and sensors are all contained in one small central unit. There is one plug for power in, and another plug for power out to the pump (included). That’s it. No more controllers to mount in your aquarium stand.

Three Water Level Sensors Onboard.

Every Prism ATO includes 3 sensors to determine your aquariums water level.

  • Low Level: If water drops below this point, the pump will be activated until water hits the next sensor.
  • Fill Level: 1″ above the low level sensor, this sensor turns the fill pump off when it detects water.
  • High Level: 1″ above the fill level, and 2″ above the low level sensor, this sensor deactivates the pump when it senses water.

All Inclusive.

The Reef Breeders Prism-ATO includes everything you need to get started- Just add water! The Prism-Ato system includes the sensor and magnet mount, a small dc power supply, a pump, tubing, and a tubing holder that fits most aquarium rims. The magnet mount works with glass up to 1/2″ thick, and does not require a clear pane of glass to function.

Every Reef Breeders Prism-ATO includes a full 12 month USA warranty.

Ships from Wakefield, RI USA

Additional information

Weight .85 lbs
Dimensions 7 × 5.5 × 2.75 in
Included Accessories

60" Tubing, Manual, Power Supply, Pump, Tubing Holder

Product Dimensions

3" x 1" x 1.25" In Tank, 1" Diameter x 1.25" Magnet Outside Tank

Maximum Glass Thickness


Ideal Tank Size/Type

AIO Chamber, In Sump, In Tank, Pico/Nano and All-in-One (AIO) Tanks over 2 gallons

Safety Features

3 Sensors Total, High Water Level Sensor, IR Visual Level Sensor

Maximum Head Height

8 Feet

22 reviews for Prism ATO

  1. Robert (verified owner)

    Works great in my Red Sea All In One rear sump! Only ATO that can be used in this scenario. Very happy thus far!

  2. Thomas E (verified owner)

    Great product. Easy to set up and works very well

  3. Matthew L. (verified owner)

    The prism ato is compact, simple, and just works. I can’t speak on longevity yet but for my short time, it has been on point. Very satisfied!

  4. Dan Brasel (verified owner)

    Simple, works, reliable. What else do you want?

  5. Larry Dunn (verified owner)

    Been using this ATO for a little over a week now and I’m very pleased with the performance and form factor of it. Price and quality are spot on!

  6. Christopher T. (verified owner)

    Fast shipping. Great product so far. Very easy to set up.

  7. Carter Macdonald (verified owner)

    This is my second ato purchased from you guys and they’re both great thanks again!

  8. Kevin C. (verified owner)

    Fast shipping, great price, great communications. Would definitely recommend

  9. Michael W. (verified owner)

    Great product! I installed this in the return pump chamber on my Biocube 32. Installation was simple and intuitive. The only thing not included was a reservoir (using a $4 plastic container). Buy with confidence.

  10. Paul (verified owner)

    Worked as I thought it would. The probe is a bit longer than i thought it would be. Solution to getting the higher water level i wanted was just tilting the angle it extended into the tank. Still too early to know how long it will work though. For the price and my application it is worth the cost compared to the more common ATO’s.

  11. James Dimpel (verified owner)

    Fast shipping. Seems to be working so far no problems.

  12. Michael H. (verified owner)

    Easy to set up, and works perfectly

  13. Stephen W. (verified owner)

  14. FRANK L. (verified owner)

    Great product – great customer service. Will buy more again.

  15. Scott Sheffer (verified owner)

  16. Dennis D. (verified owner)

    Great products. So glad I found Reef Breeders!

  17. Shae Conaway (verified owner)

    Great shipping and packaging. Haven’t used it yet but looks like quality made ato

  18. Kenneth Barney (verified owner)

  19. TJ Lysiak (verified owner)

    The prism is a must have for any nano or pico tank!

  20. Barbara H. (verified owner)

    Always the best customer service. And products

  21. Dan Brasel (verified owner)

    Simple, works well.

  22. Tebias Brookins (verified owner)

    Easy installation and fast shipping!

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