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FMK - Flow Monitoring Kit - Complete System - Neptune Systems

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Product Description

The FMK flow monitoring kit is now available for Apex controllers by Neptune Systems.  With your Apex controller you can now monitor your flow of your pumps with the Apex Fusion software!  Using the FMM module the Apex controller can now monitor the flow on your pumps either for your return pump, reactors, and so much more.

Here is everything included with the FMK flow monitoring Kit:

  • 1'' FLOW SENSOR (FS-100)
  • FOUR 1/2'' FLOW SENSORS (FS-50)
  • TWO 1'' UNIONS
  • TWO 1/2'' ADAPTERS

Return pump
Measuring the flow of your aquarium’s main return pump is an incredibly useful piece of information. The key benefit would be to have the Apex notify you the instant the flow stops for any reason — usually the result of a failed or faulty pump. Furthermore, an indication of a reduced flow rate could be used to determine that the pump or the lines are dirty or are becoming clogged with algae, debris, animals, or the growth of organisms inside your plumbing.

Auxiliary pumps on reactors
This is a very handy application for the FMM. Place a flow sensor on a device like a carbon/gfo reactor and it serves many purposes. First off, you will know if your pump is not on or is faulty. Next, you can easily fine-tune the flow into the reactor by watching the dashboard tile on your Apex. Finally, you can know when the reactor is becoming clogged with detritus or possibly channeling has occurred by an alert on your Apex or by monitoring your dashboard.

Put a flow sensor inline to your device, plug it in to the FMM, and see exactly the flow rate of the water (any aquarium fluid really) going through that sensor. The industrial-grade flow sensors work use either a turbine or paddle-wheel mechanism (depending on the model) to measure the flow.

With the FMK – Fluid Monitoring Kit you get one 1″ Flow Sensor and unions as well as two 1/2″ Flow Sensors with adapter fittings. 


The FMK comes with three flow sensors but the FMM has a total of four ports. This means you have one port free to use for another purpose. Buy an additional flow sensor (available also in 2″ and 1/4″ sizes) or choose from one of the options below and add even more functionality.


There are many useful purposes for water-level sensors on an aquarium. They can help you build an auto-top-off, monitor the levels in your supplement containers, even help automate saltwater mixing containers. Traditionally float switches have been the most commonly used types of these devices, however they are prone to all kinds of failure. On the other hand, the solid-state, optically-controlled sensors used with the FMM are much more reliable and dependable.

These optical sensors work by using an LED emitters and receptor in clear enclosure such that when it becomes wet, the light bends and no longer completes the circuit.

Easy to use
Of course you could always add water-level sensors to your Apex – but it was more complicated than most users could handle. Now, with the FMM and these optical water-level sensors, you just plug them in! No wire-stripping, no breakout box necessary!

ATK – Auto Top-off Kit
If you are looking to use the FMM for an ATO, there is no reason for you to DIY it by putting together all the pieces individually. Instead, get our ATK and get everything you need to make up for evaporation, keep a consistent water level and salinity, and do it with three layers of backup protection.


In addition to flow monitoring and level-detection, the FMM can be used for leak detection. Simply plug in up to four of our new, super-sensitive leak detection probes and place them where you want that oh-so-important protection for your floors, and your marriage!

LDK – Leak Detection Kit
If you are looking to get going with leak detection and the FMM, we have put together a great little kit that combines the FMM along with two of our LD-2 leak detection sensors designed for solid surfaces with four ounces of weight built in to keep them firmly on the ground. When you get the LDK, you also save a few dollars over buying the components separately.


The FMM has another trick up it’s sleeve. In addition to the four sensor ports, the FMM also has a 1Link DC24 accessory port and a power supply input. This can be used to add another controllable outlet to your Apex set up. So, for instance, if you do want to roll your own ATO and attach our available PMUP or Solenoid Valve you can do so. Simply add our 36W 24V DC power supply (available separately).

Product Videos

FMK - Flow Monitoring Kit :: Know your Flow! :: An Accessory for your Apex by Neptune Systems 09:26

In this video learn all about the new FMK from Neptune Systems. The FMK includes the FMM (Fluid Monitoring Module), one 1" flow sensor, and two 1/2" flow sensors. More product info can be found at or In the USA the FMK will be just $199.95

  • FMK - Flow Mon...
    In this video learn all about the new FMK from Neptune Systems...

Product Reviews

Write Review

  1. Simply amazing

    Posted by Unknown on May 24th 2017

    Get your devices to perform according to their specifications by knowing how much flow is directed towards them and then finely tuning the flow to the devices specifications or desired effect in your tank.


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