Neptune Systems built its reputation on one core idea: a reef tank runs more stably when monitoring, dosing, and equipment control all report to a single brain instead of a shelf of standalone timers and testers. The Apex controller is that brain, and almost everything else Neptune makes (dosing pumps, automated testers, probes, flow sensors, leak detectors) is designed to plug into it. This guide maps the ecosystem from the controller outward, using real Neptune Systems items IndieFur carries. If you’re currently testing calcium by hand, our Salifert Calcium Test guide is a useful contrast point for exactly what automation like Trident replaces.
The controller: where everything reports
The Neptune A3 Apex Aquarium Controller System is the current generation’s core unit, monitoring temperature, pH, and other parameters while controlling connected equipment through programmable outlets. The Neptune A3 Apex Jr Aquarium Controller System is a smaller-footprint version suited to nano and mid-size tanks that don’t need the full outlet count, and the Neptune A3 Apex Pro Aquarium Controller System adds extra probe and expansion ports for larger, more heavily automated systems. All three are currently on backorder. Check the product pages for the latest availability before planning a build around them.
For hobbyists who want a starting bundle rather than piecing components together individually, Neptune also offers combination packages: an Apex system bundled with an extra Energy Bar 832 power bar for more controllable outlets, an EB4 and A3 Apex Jr bundle pairing the base unit with an Energy Bar 4 and essential probes, and a Trident-and-Apex bundle covering both control and automated testing in one purchase.
Automated testing: Trident
Manual reef test kits are accurate but easy to fall behind on. Neptune’s Trident line automates the parameters that matter most for coral health. The Neptune Trident NP Nitrate and Phosphate Tester and Neptune Trident ACM Alkalinity, Calcium and Magnesium Tester run scheduled tests automatically and log results over time, so drift shows up as a trend rather than a surprise at your next manual test. Both ship without reagents; the Neptune Systems 2 Month Trident NP Reagent Kit is currently in stock, while the 2 Month Trident Reagent Kit for the ACM tester is on backorder.
Dosing: DOS and its replacement parts
The Neptune DOS Quiet Drive Dosing Pump (currently on backorder) is Neptune’s precision dosing pump, built to run calcium, alkalinity, magnesium, or trace element supplementation on an automated schedule tied to Apex Fusion. Keeping one running long-term means occasionally replacing wear parts: Neptune’s replacement pump head assembly swaps tubing, roller, and housing cap in minutes, and replacement tubing is available in both 16-meter and 4-meter lengths for extending the run between pump and reservoir or tank. These replacement parts are newly listed and not yet fully live on the storefront. Check with IndieFur directly to confirm current availability and pricing before ordering.
Feeding
The Neptune AFS Automatic Feeding System (on backorder) is built specifically for reef tanks, with a stay-dry food chamber and the ability to briefly pause skimmers and return pumps at feeding time so food doesn’t get pulled straight into filtration before fish can eat it. If you’re comparing automated feeding options more broadly, our Automatic Fish Feeder Guide covers the freshwater side of the category.
Flow and return pumps
Neptune’s COR return pumps connect directly to an Energy Bar 832 or 1Link module with no separate power adapter, and unlock advanced flow control through Apex Fusion when paired with a controller. The COR-15 moves up to 1,500 GPH and the COR-20 up to 2,000 GPH; both are newly listed items, so confirm live stock before ordering.
Refugium lighting
The Neptune GRO Refugium Light packs 84 LEDs in a growth-optimized spectrum into a compact, IP64 water-resistant fixture built for growing macroalgae like chaetomorpha as a natural nutrient export tool. It’s available with either a flat bracket mount for a sump edge or a gooseneck pipe-clamp mount, depending on your sump’s layout; both are newly listed items pending full storefront availability.
Monitoring modules and probes
Beyond the core controller, Neptune’s PM-series modules add specific monitoring capability: the PM1 module adds pH or ORP monitoring, the PM2 module adds continuous real-time salinity monitoring (catching an early warning from a stuck top-off unit before it becomes a bigger problem), and the PM3 module adds dissolved oxygen monitoring within the reef-safe 4.5-7 ppm range. The FMM Fluid Monitoring Module adds flow monitoring, leak detection, and water level management across four ports, and pairs with Neptune’s FS-series flow sensors (available in 1/4″, 1/2″, 1″, and 2″ sizes matched to different plumbing) for real-time flow visibility on pumps and reactors. The LDK Leak Detection Kit adds expandable leak sensors via the AquaBus connection; catching a leak early can save a tank from total loss. These modules and probes are newly listed; confirm current stock before building a monitoring plan around a specific one.
Expansion and utility
The 1Link Power and Communication Module lets a single outlet run up to three WAV pumps (or two WAV pumps plus a DOS pump) and unlocks Apex Fusion’s flow modes for them. The I/O Breakout Box adds up to six external switch connections for float switches, push buttons, and magnetic switches, and the Apex Display Module puts key water parameters on a backlit LCD screen at the tank itself, letting you trigger feed modes without a phone or computer. The ATK V2 Auto Top Off Kit is a complete plug-and-play kit with dual optical sensors and a mechanical float valve backup that works standalone, without requiring an Apex controller at all. All of these are newly listed items. Check availability before finalizing a build.
Bridging to other brands: MXM Mobius
The Neptune MXM Mobius Wireless Control Module wirelessly connects EcoTech Marine and AquaIllumination gear (pumps, lights) to an Apex, so equipment from both brands can be automated through Apex Fusion in one interface. It’s compatible with all A2 and A3 Apex systems and is the practical link between a Neptune-controlled tank and EcoTech lighting; see our EcoTech Marine Reef Lighting Guide for the lighting side of that pairing. This module is also newly listed. Confirm live availability before ordering.
Quick reference
| Need | Product |
|---|---|
| Core monitoring & control | A3 Apex, Apex Jr, Apex Pro |
| Automated water testing | Trident NP, Trident ACM |
| Precision dosing | DOS Quiet Drive Dosing Pump |
| Automated feeding | AFS Automatic Feeding System |
| Return flow | COR-15, COR-20 |
| Refugium growth | GRO Refugium Light |
| Salinity / DO / pH monitoring | PM1, PM2, PM3 modules |
| Flow & leak monitoring | FMM, FS flow sensors, LDK |
| Auto top-off without Apex | ATK V2 |
| Cross-brand light/pump control | MXM Mobius Module |
Building the system in order
Most reefers start with the Apex controller itself, since nearly everything else in the range either plugs directly into it or is far more useful once it does. From there, prioritize based on what’s currently manual and error-prone in your routine: Trident if hand-testing calcium and alkalinity keeps slipping, DOS if you’re hand-dosing daily, AFS if feeding schedule consistency is the gap. A significant share of this range is newly listed inventory rather than live stock, so treat this guide as a map of what’s coming online rather than a same-day shopping list, and confirm availability on each product page before you commit a build around a specific part.
