The Neptune Apex A3 Aquarium Controller is a premium aquarium monitoring and control system built for reef, saltwater, and advanced freshwater aquariums where stability, automation, alerts, and equipment oversight matter.
The Apex A3 sits in the middle of Neptune's A3 lineup, giving aquarists a strong balance of real-time monitoring and active equipment control. It includes the Apex A3 base unit, Energy Bar 832, pH monitoring, temperature monitoring, leak detection, a magnetic optical sensor, and expandable accessory ports. For hobbyists running heaters, return pumps, skimmers, dosing systems, refugium lights, alarms, or emergency shutoff routines, the Apex A3 provides the foundation for a smarter and more protected aquarium.
Unlike a simple monitor, the Apex A3 can control connected equipment based on schedules, sensor readings, alarms, and custom programming. That means the system can do more than report a problem; it can also help respond by shutting off a pump, disabling a skimmer, turning on a fan, sounding an alarm, or sending a notification through Apex Fusion depending on how the system is configured.
Neptune Apex A3 Features
Full aquarium monitoring and control: Monitor key aquarium conditions while controlling compatible equipment through the included Energy Bar 832 and Apex programming.
Temperature monitoring included: The included temperature probe helps track system temperature trends and can be used to control heaters, chillers, fans, alarms, and emergency actions.
Lab-grade double-junction pH probe included: Continuous pH monitoring helps reef keepers track day-night swings, dosing effects, kalkwasser use, calcium reactor behaviour, and unexpected chemistry changes.
Energy Bar 832 included: The included Energy Bar provides eight controllable 120V AC outlets, three 1LINK ports, two DC24 accessory outputs, individual outlet status LEDs, and per-outlet power monitoring.
Power monitoring for connected equipment: Monitor power use on Energy Bar outlets to help identify abnormal equipment behaviour, such as a pump drawing no power when commanded on or a device using more power than expected.
Magnetic optical sensor included: The included magnetic optical sensor can detect whether water is above or below the sensor position, making it useful for sump levels, ATO logic, reservoir protection, overflow alarms, or custom water-level routines.
Solid-surface leak detection included: The included leak sensor can alert when water is detected where it should not be, helping protect floors, stands, cabinetry, and nearby equipment.
Three built-in FMM ports: The A3 includes three FMM accessory ports for compatible Neptune sensors and fluid-monitoring accessories.
Wi-Fi and wired Ethernet: Connect the Apex A3 to Apex Fusion over Wi-Fi or use hard-wired Ethernet where a physical network connection is preferred.
Apex Fusion cloud access: Apex Fusion allows monitoring, control, alerts, programming, and system access from compatible phones, tablets, and web browsers.
Expandable Apex ecosystem: The A3 can grow with additional Neptune modules and accessories such as Trident, DOS, ATK, flow monitoring, leak detection, probe modules, lighting accessories, and other Apex-ready equipment.
Apex A3 Controller Specifications
Controller model: Neptune Apex A3 Aquarium Controller
Monitoring included: Temperature and pH
Included leak sensor: Solid-surface leak detection sensor
Included water-level sensor: Magnetic optical sensor
FMM accessory ports: 3 built-in FMM input ports
Controllable AC outlets: 8 outlets through the included Energy Bar 832
1LINK outputs: 3 outputs through the included Energy Bar 832
DC24 accessory outputs: 2 switchable DC24 outputs through the included Energy Bar 832
Digital inputs: 6 digital inputs for compatible switch and breakout-box applications
Network connection: Wi-Fi or hard-wired Ethernet
Audible alarm: Built-in alarm buzzer
Expansion: Compatible with Apex A3 Series modules and accessories
Display module: Sold separately
Energy Bar 832 Power Control
The included Energy Bar 832 is one of the major reasons to choose the Apex A3 over the Junior model. It provides switched outlet control for common aquarium equipment such as heaters, return pumps, protein skimmers, refugium lights, dosing equipment, fans, and utility pumps. Because each AC outlet has power monitoring, the Apex can be configured to alert when equipment is not behaving normally, such as a pump drawing no power while commanded on or a device using more power than expected.
The Energy Bar 832 also includes three 1LINK ports for compatible Neptune devices and two switchable DC24 accessory ports for supported 24V accessories. This gives the A3 a strong foundation for clean controller-board layouts, reduced power-brick clutter, and more integrated Apex automation.
Aquarium Use and Compatibility Notes
The Apex A3 is well suited for reef tanks, mixed reefs, fish-only marine systems, larger freshwater displays, and any aquarium where the owner wants more protection than individual standalone devices can provide. It is especially useful for automating heater redundancy, temperature alarms, pH monitoring, skimmer delay after feeding, return-pump shutdown during maintenance, ATO protection, leak alerts, and remote status checks.
The display module is not included with the Apex A3 and is available separately. ORP and salinity monitoring can be added with compatible probes and modules where supported, but the included package is focused on temperature, pH, leak detection, water-level sensing, and Energy Bar control.
Setup and Installation Directions
Mount the Apex base unit and Energy Bar in a dry, well-ventilated location away from splashes, salt creep, and high humidity. Create drip loops on all cables, keep probe cables away from high-voltage cords where practical, and place probes in a stable high-flow area such as the sump. Connect the Energy Bar to the Apex with the Aquabus cable, connect the included probes and sensors, then follow the Apex Fusion setup process to connect the system, configure outlets, name equipment, calibrate probes, and set alerts. Test every alarm and control routine before relying on it for livestock protection.
What's Included
A3 Apex Base Unit
Energy Bar 832
6 ft Aquabus Cable
Lab Grade Double Junction pH Probe
Temperature Probe
Solid-Surface Leak Detection Probe
Magnetic Optical Sensor
pH calibration solutions
