ATO EZ Auto Top Off System - IceCap

Evaporation-driven salinity swings are a persistent source of stress for reef aquariums, and the IceCap ATO EZ is designed to address that without complexity. The system pairs a magnetically mounted three-sensor optical housing with a brushless DC refill pump. Together they maintain sump water level automatically, with a fail-safe architecture that goes beyond what single-sensor ATO units can offer.

The sensor housing uses two active optical sensors to define a normal operating band rather than a single trigger point. When the water level drops below the lower sensor, the pump activates and the indicator blinks blue. Once water rises to the middle sensor, the pump stops and a solid blue light confirms normal status. This band-based approach means the pump runs in longer, less frequent cycles rather than switching on and off repeatedly — a meaningful factor in pump longevity over months and years of continuous use.

The third sensor, positioned above the normal range, functions as an independent safety cutoff. If a float sticks, a hose slips, or the sump level rises unexpectedly, this sensor shuts the pump down immediately and flashes red. Status is visible at a glance without needing to check an app or controller — the indicator lights communicate the current state directly.

Setup requires no plumbing modifications. Slide the sensor housing onto any flat sump wall using the included magnet, place the DC pump in your top-off reservoir, and route the included 6.5 ft of tubing. The kit ships with a universal tubing holder and siphon breaker, so the basics of a clean, drip-back-resistant installation are covered out of the box. The ATO EZ operates as a standalone system and does not require integration with a controller, making it a practical option for both new builds and existing setups without automation infrastructure.