Neptune Systems

Neptune Systems COR-20 Intelligent Return Pump


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  • Runs Standalone
    That’s right, the COR-20 will run completely standalone OR connected to ANY Apex System via its AquaBus port. If you don’t yet have an Apex, don’t worry, down the road when you get one, you’ll open the door to many more features (like mobile notifications).
  • Up to 2000 GPH (7500 LPH)
    When properly plumbed, one COR-20 provides enough flow for aquariums up to 180 gallons. For larger systems, use two COR-20 for redundancy and disaster prevention.
  • For internal or external applications
    With it’s included fittings, the COR-20 can be plumbed to work either externally, or submerged in a sump.
  • IQ-Level sets the proper min and max for your aquarium
    Every aquarium is different so the IQ-Level feature of the COR-20 enables you to set a customized minimum and maximum flow rate for your specific aquarium’s needs.
  • Includes oversized 1.25 in. union
    We include a 1.25" BSPP -> 1.25" Slip PVC Unions so that you get the optimal flow from your COR-20. Plumb your system with 1.25" and see what this pump can really do!
  • Energy Efficient - Uses less than 50W of Power
    The COR-20 is a brushless, DC-driven pump optimized for the lowest power consumption possible. At 100% it still uses less than 50W at the wall!
  • Incredibly Quiet!
    We think the COR-20 is the quietest pump on the market for its size and output. We challenge you to find a quieter pump!
  • No Power Brick means cleaner install
    Because the COR-20 uses the existing power supply inside the Energy Bar 832 or the one shared on the 1LINK module, there are no extra power bricks and power cords required to operate it. This means that you have less gear to store under your stand and less wires to manage!
  • Compatible with all Apex Systems
    The COR pumps are compatible with all Apex systems including: Apex, Apex Classic, Apex Lite, and Apex Jr. Simply connect the COR driver to the Apex via any available AquaBus port.

Intelligent, Quiet, Energy-Efficient

Your return pump is by far the most important piece of equipment on your aquarium. It circulates the water which is basically the life-blood of a tank. Creating a great aquarium is just like building a great body – it all starts at the core – and this is precisely how our pump got its name!

The COR is a variable speed, brushless, DC-driven centrifugal water pump designed specifically for aquariums to be intelligent, energy-efficient, unbelievably quiet, and incredibly powerful for its size.

No Apex Necessary!

The COR-20 does not require an Apex to operate. If you do not yet have an Apex don’t worry, much of its functionality is available from the button and LED interface on its driver. However, connect it to your Apex and it becomes the most intelligent and feature-rich aquarium pump on the market today!

Compatible With Every Apex

All COR pump models are fully compatible with every Apex system on the market. Simply connect the COR-20 pump driver to any available 1Link port on your Apex system – either an Energy Bar 832 or a 1Link module. It’s that easy!

Great Flow To Power Ratio

The COR-20 puts out great flow while at the same time being super-stingy on power making it friendly to you wallet and the environment! Be sure to plumb the COR-20 using the largest diameter pipe possible to get the best performance. We recommend at least 1.25"

Advanced Controlability

The COR was built from the ground up with Apex controllability in mind. Control your pump output percentage, get real-time operational feedback from the pump, integrate it into complex feed routines, and monitor the status of the pump from anywhere in the world via Apex Fusion.

Easy Installation

Connect the plumbing, plug the COR into its driver and plug it in a 1LINK port. With just a few button presses you will be able to set the pump flow rate and feed modes. A set up task will take you step by step through the entire install process.

Whisper-Drive Technology

The COR uses the latest in Vector Control, BLDC motor technology. This drives the COR pump in a way that is both energy efficient as well as nearly vibration and noise free.
Go ahead, we challenge you to find a quieter pump!

Obstruction Detection

Snails, filter pads, or other foreign objects often find their way into a pump. Should the intake to your COR or any of your plumbing become significantly obstructed, the COR will alert you by flashing the LED on the driver. When the COR is connected to an Apex and the internet, it will send an alert to your mobile device as well.

Internal Temperature Monitoring

The pump driver is continually monitoring the internal temperature of the COR pump motor. If it reaches an unsafe level, the driver will slow the pump down just enough to bring the temperature into an acceptable range while also providing you a notification. Some pumps shut off completely when they have a temperature issue, but the COR slows down so your tank will continue to circulate — giving you time to address the problem.


Set the output level you desire for your aquarium and overflow capability and the COR will memorize that and make it your "100%" for your aquarium. If power should go off, when it restarts it will always return to that memorized setting. Also, during feed modes, your water will not completely back-siphon. This prevents the burping and bubbling that normally occurs when a pump powers back up.

Feed Mode

With some simple configuration in Apex Fusion you can set a Feed Mode that will slow the pump to any level you choose. You can even have other tank operations sequence with this feed mode and the time interval of the Feed Mode can be customized as well. The buttons on the COR driver also function as an easy to use feed button.

Included Fittings

The COR comes complete with all the fittings necessary for most aquarium configurations (0.75" output, 1.0" input). But we’ve also included a 1.25" union for the output so you can connect the pump in a manner that will result in the least amount of head loss. Plumb your main return-line in 1.25" and get the full potential of the COR pump – as much as 50% or more flow!


  • Plumbing fittings, hose, pipe, etc.
  • Basic plumbing knowledge


  • COR Pump
  • COR-20 Pump Driver
  • 100W 24VDC Power Supply
  • Power Cord
  • 1.25in. PVC Union (Slip->BSPP)
  • 1.0in. Slip Fitting
  • 0.75in. Slip Fitting
  • 3-foot AquaBus Cable


  • Pump: 3.875”W xv4.875”H x 6.250”D
  • Driver: 3"W x 4"H x 1"D

Product Manuals & Documentation

Neptune Systems COR-20 Intelligent Return Pump

Owner's Manual available for download in Adobe PDF file format

Manufacturer Info

Neptune Systems Aquarium Supplies
Neptune Systems is one of the world’s leading manufacturers of aquarium controllers. The company was founded in 1995 for the purpose of developing affordable water quality monitoring and control instrumentation. Their engineering team has extensive expertise in computer hardware and software system design as well as a background in water quality analysis. Neptune Systems uses these finely-honed engineering skills to develop innovative monitoring and control solutions for use in reef and fresh water aquariums, aquaculture tanks, hydroponics systems and general laboratory use. Neptune Systems is best known for their AquaController line. The company is known for their innovation and customer centricity.

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9 Questions
Displaying questions 1-9
When will this pump be available?
Asked : Mar 12, 2018
By : John Alexander, Villa Park, ca
In stock now!
Answered : Apr 30, 2018
By : TBF, CA
Where is the flow vs. heAD PUMP CURVE?
My storage, treatment, filtration, etc. is located in the basement, the aquarium is on the main floor. I need the pump curve to calculate flow to the aquarium, and to properly size the pump.
Asked : Dec 21, 2017
By : Don Gallaher, Denver
The Neptune Systems site shows the Flow vs. Head-Height plot on the main COR-20 page:
Answered : Apr 03, 2018
By : JKing
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Overall, others give this:

  • 5.0

2 Reviewers (100%) would recommend this

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Very impressed!

Quiet, easily controllable, very strong, durable
The inlet portion of the pump is not protected, marine life could easily be sucked into it!
Apex stepped up their game with this! Wow! This pump is extremely quiet and such a beast at what it is designed to do! The best I have seen this far! It is very much worth every penny spent! It's an amazing addition to my reef tank set up. I highly recommend this product.
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Worth every penny!!!
Plenty of push left over
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Got one of these bad boys at a lfs but I needed to leave a review here. I needed 10 feet of lift from my basement. This thing out performs anything else by far! To my 125 double return with 3 45s in the line I only can run it at 40%. Absolutely love this pump
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Overall, others give this:

  • 5.0

2 Reviewers (100%) would recommend this

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