FM-2: Filter Monitor with Volumizer - HM Digital

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FM-2: Filter Monitor with Volumizer - HM Digital

73% Recommend this to a friend (16 of 22)

SKU: 200218

reg. $39.99

Special Price: $33.99

In Stock: 29
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Quick Overview

The FM-2 RO Filter Monitor with Volumizer tracks up to five filter stages at once by time and volume. The monitor allows you to create filter change points at each stage at an individual point in the future or at a specific water volume. When the pre set points are reached the FM-2 will alert you that it's time to change a particular stage. This is a great unit for maintaining your RO Unit.


  • Five independent timers

  • Monitors up to 5 stages

  • Timer counts down in month or days

  • Volumizer counts up in gallons or liters

  • Digital display

  • LED light indicator and audible alarm (beep)

  • Easy installation

  • See below for full details


Full Details

  • A five-stage filter monitor with five independent timers and a tri-color LED faucet indicator disc.
  • The volumizer counts up in gallons or liters (settings can be modified).
  • Works on time (and volume for the FM-2) for up to five stages (can be less).
  • The LED indicator disc will illuminate a green, yellow or red light when the water is turned on.  The color indicates the percentage of elapsed time.
  • Auto-Off function conserves battery power. The unit shuts off automatically after 5 minutes of non-use.
  • The timer counts down in months or days (settings can be modified).
  • Includes an audible alarm (beep).
  • Modern design is perfect for any kitchen.
  • Installs quickly and easily.



Timer Range: 0-999 days/months
Timer Modes: Days or months (default is months) 
Settings: One alert per stage, up to five stages 
Default Setting: 12 months 
Batteries: 2 x AA (included)
Battery Life: approx. 18 months 
Base Unit Dimensions: 100 x 63 23 mm (4 x 2.5 x 0.9 in) 
Base Unit Weight: 119 g (4.2 oz.) (including batteries)
Flow Switch Cable Length: 93 cm (36.6 in) 
Flow Switch Fitting Size: 1/4" Quick Connect 
LED Faucet Indicator Disc Cable Length: 92 cm (36.25 in)
LED Faucet Indicator Disc Dimensions: 4.75 (1 1/4" in.) dia., 8 cm (5/16") high 


Patents Pending



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  • Ensure it is set up correctly By jokerman826 on 2/10/2017

    I havr had this thing a while. I have seen a lot of bad reviews on this thing. I was very frustrated with it today. I replaced the filters and batteries and could not get the volumiz er to turn on. I gave up after a while and just set it up to count the months.

    I went back to it later on and went through the directions again. disconnect the sensor, remove a battery, reconnect the sensor and then reinstall the battery (while you have flow). didn't work no matter how many times I did it. I finally decided to take down the sensor to make sure it wasn't broken inside. I noticed this little arrow on the sensor to indicate flow direction. I put the sensor back together and the reinstalled in the correct ditection. I redid the volumizer setup and bam, it worked.

    To sum it all up. set up the flow senor in the correct direction. I repeat set up the sensor in the correct direction.

    I gave it a 3 star review because of the lack of detailed documentation regarding the setup of this item.
  • Does not work By Chris on 1/19/2017

    As noted by other reviewers, I am extremely disappointed that this product does not work. I have owned this for over a year now. I have tried even reversing to see if perhaps is labeled backwards, but no improvement.

    I run a 110 gallon reef and a 20 gallon quarantine for almost a year now. Based on the volumizer, I have only moved 450 gallons of raw (untreated) water. This is before the RO rejection. I have now been though 600 gallons of salt mind you, and I go through 10 gallons of RO/DI a week. These number are post-RO, so figure I waste 2-3 gallons of water for every gallon produced. I should be seeing 4,400 gallons of water but the unit shows 450.

    I was going to contact BRS, but seeing the comments above I decided it was not worth my time.
  • Very Happy with the Product By Ramturbod on 9/26/2016

    I wanted to be able to monitor my RO/DI system for changes in media and be able to see how much water is actually be used overall. So far I have been very please. I found that I am producing one gallon of product to 4 gallons of total water. The unit was very easy to install and did not have any problems in the setup.
  • Doesn't work By Bigbubbatubba on 1/18/2016

    What a great idea! Unfortunately the product does not appear to work. I sent the first one back, received a replacement, and. same thing happened - only let me adjust time for one channel and no volumizer function at all. So returned it and they reshuffled another. This is my third unit and absolutely the same identical problem as the first two units. Shame on BRS for making me call the manufacture like it was something I was doing. Bad product...
  • It didn't work for me. By Mark on 1/2/2016

    I printed the on-line instructions. Spent a lot time learning. Tried off and on for over a month. The volume never counted. I unplugged the flow sensor, removed battery etc. I programmed all 5 stages. None of them ever counted. This product is discontinued. I can see why.
  • Great tool to monitor your Filter usage By Xavier on 11/21/2015

    Just make sure that everything is connected prior to Battery install. if not the voluminizer will not show on screen, I lost 20 min realizing that ! (stupid of me)
  • Save money By Jose on 1/19/2015

    Great add on works perfectly
  • Just a counter By Paul on 10/22/2014

    I wish these were cheaper as I only use them to count gallons. I put 2 of them on, one before my filters and one after my RO membrane. It's perfect as it tells me how much water I've made, how much water I've used, so I know my ratio, and when I need to change out my filters and gives me an idea of how much water I've sent through my resin so I have an idea of when to change it. Works for me.
  • an item to keep you on point By turbotone on MR on 1/15/2014

    this item is great for a forgetful person.. if this is you get this item!! lol its me for sure but how it benefits you is by monitoring the gallons you use on some of the filters rather then time.. i own a 5 stage system (pre filter, chloraplus carbon filter, matrix carbon filter, 75 gpd membrane and 75 gpd membrane with 2 di stages that i don't monitor because i can visible see and i also have dual tds meter monitoring both of them) pre filters i would change every three months and carbons every 6 months as a rule of thumb.. with this system you change pre filters every 3000,carbon every 6 months membranes are on a time schedule of every 36 months.. i haven't changed my pre filter yet and its been 6 months..just got to the 1200 gallon mark. it makes sense bc I'm running a 75 gallon mixed reef with a 30 sump. i do a 10 gallon water change per week and fill up my 10 gallon ato tank at the same time using about 9 gallons per week total use about 20 gallons a week… i use to do 20 gallon water changes a week at first… keep in mind i have it monitoring after the booster pump but before the very first filter… definitely an investment long term due to the savings in just filter use.
  • Looks good By BobbyT on 12/8/2013

    I think this is a very important device to install on any RO unit.
    Everything is working great so far
  • I would highly recommend for someone that has muliple statages of filter to change a different times. By Kenneth on 11/9/2013

    i highly recommend this tool. It helps to keep track of how much water you are going through, so no more guessing on when to change the filter or how much life you got out of the filter. You can setup a separate checker for each of your stages. I have color changing DI so i know when it needs to be changed, but I still like to know how many gallon of DI water was produced so that I can keep track of my expenses and how the system is functioning.
  • DOA By Russel on 10/29/2013

    The unit has two modes - timer and volumizer. Obviously the more desirable function for the price is the volumizer. Unfortunately the unit I received never detects any flow rate. I was able to get it to detect the flow meter by reinserting the battery - but no matter where I put the unit on my RODI system, it never detects any flow. I even tried blowing air into the flow meter just to ensure the impeller worked - heard it spin, but no reading. Contacted manufacturer to see what the next steps are.... probably going to have to pay return shipping.


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Product Questions

Hi, in case of battery replacement or outage will the devise memorise my own setup?
Question by: Ghassan on Jan 17, 2017 12:19:00 PM
Great question! The unit will not save your settings after the battery is removed. You will need to reset the unit to your settings once the battery is replaced. :-)
Answer by: Randy (Admin) on Jan 17, 2017 5:41:00 PM
Can you provide the original setup instructions for starting as new? The HM Digital site only has a sheet for restarting with original settings not disturbed.
Question by: LANNY on May 13, 2016 9:58:00 AM
To factory reset your FM2 you will do the following:

1) The factory default settings are 12 months/days and 100 gallons/liters for each stage.

2) To reset to the default settings (if you have changed it), with the unit on, quickly press the SET button. The unit will beep and the "SET" icon will be displayed.

3) Press and hold the SET, UP and DOWN buttons together for 2 seconds. The unit will beep three times. This will reset all five stages to 12 m/d and 100 g/l (deleting any saved settings.)
Answer by: Carter (Admin) on May 18, 2016 6:29:00 PM
Do you recommend putting the flow sensor on the product water line or the water inlet before the filters.
Question by: Matt on Apr 18, 2014 6:54:00 AM
Hi Matt,
It will only function on the water inlet line. Fortunately this is the value you want to know anyway, as all of the water (product and waste) both travel through your prefilters.
Answer by: Bulk Reef Supply on Apr 18, 2014 6:54:00 AM
Would this work with the water saver upgrade kit? Will the volumizer get confused?
Question by: Kevin on Dec 23, 2013 6:12:00 AM
Hi Kevin,
The volumizer only records the water going into the RO/DI unit and it will continue to do so. Since your filters are rated for the amount of total water they are processing and that will remain the same, the volumizer is still good to go (you'll just find that of that total water processed more of it is product water vs waste now so you don't have to run the unit as long to get the same amount of product water). Hope that makes sense!
Answer by: Bulk Reef Supply on Dec 23, 2013 6:12:00 AM