Bulk Reef Supply

Reverse Osmosis Membrane Flush Valve

Grouped product items
400 mL Flow Membrane Flush Valve

SKU: 208445

In stock


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550 mL Flow Membrane Flush Valve (Recommended for 75 GPD Membranes)

SKU: 211642

In stock


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800 mL Flow Membrane Flush Valve

SKU: 208447

In stock


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The Membrane Flush/Flow restrictor valve is an all in one flow restrictor equipped with a flush valve for easy worry free use.

Keeping the flush and flow restrictor in a single package keeps fitting count down which means less chance for possible leaks or failures down the line.

  • 550 mL/min for 75 GPD single membranes or 150 GPD Water Saver Systems
  • 800mL/min for 100 &150 GPD single membranes or 200 GPD Water Saver System


Reverse Osmosis membrane flush/flow restrictor valves increase the flow to the membrane by bypassing the flow restrictor when the valve is opened. This helps flush deposits and significantly increases the usable life of the RO membrane. The Membrane Flush/Flow restrictor valve is an all in one flow restrictor equipped with a flush valve for easy worry free use. Keeping the flush and flow restrictor in a single package keeps fitting count down which means less chance for possible leaks or failures down the line. BulkReefSupply.com recommends flushing the membrane before and after each use for a few seconds, or every few weeks for a few minutes as part of regular reverse osmosis system maintenance. When the handle on the valve is “in line” the valve is bypassing the flow restrictor and is in “flush mode,” if the handle is perpendicular to the valve then the unit is ready for normal use.

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Product Questions

How often should the restrictor valves be replaced? Should they be replaced when changing out the membranes or when they fail? THx
Question by: Alex B. on Jun 6, 2023, 1:57 PM
These do not need to be replaced unless they spring a leak or fail.
Answer by: Ash (BRS Staff) on Jun 8, 2023, 5:13 PM
I have the 150GPD 6 stage RODI water saver upgrade system and have the 550ml flush valve. Is that the right flush valve?

Thank you.

Question by: Michael Penny on Mar 27, 2022, 11:18 AM
Hey there,
Thank you for reaching out to us. Yes, that is the correct flush valve.

Please let me know if you need anything further and take care!
Answer by: Matt Lucero (BRS Staff) on Mar 29, 2022, 10:23 AM
The RO/DI unit that I'm running now is the BRS 75 gpd system paired with a triple resin system. I have a 600 ML flow flush valve from a previous system. Can I use that 600ml valve with this system?
Question by: Billy Carroll on Mar 10, 2020, 5:45 PM
Hi there,

With the 75GPD membrane we recommend a 550ml or 500ml flow restrictor.

Take care
Answer by: Thomas Billington on Mar 11, 2020, 3:17 PM
After I am done producing water, I put the flush valve to the inline, flush position, but nothing happens. I have to start water production again in order for the flush to take place. What am I missing? Thank you!
Question by: Sean Stuart on Mar 4, 2020, 6:51 PM
Hey there,

Please give us a call on Monday, there are a few things that could cause this. 763-42-9691
Answer by: Thomas Billington on Mar 7, 2020, 9:13 AM
I’m a noob when it comes to this stuff, I have my flush valve installed I’m just wondering how do I use it for operation? When Im using the filters do I leave it closed or open? And how do I perform a membrane flush?
Question by: Karl Kildea on Aug 5, 2019, 10:15 PM
Hey there!

When the black valve is at 90 degrees or perpendicular to the flow restrictor it is closed and should stay like that for normal operation. When the black valve is inline or parallel it is open and flushing the membrane and pre filters.
Answer by: Thomas Billington on Aug 6, 2019, 12:40 PM
I have a BRS 5 stage 75GPD RODI unit with a 550mL flush valve and a booster pump kit. My tap water is very dirty (700+ TDS) and I'm getting around 50 TDS after the membrane. I was wonder if got a bigger flow membrane flush valve if that would increase my rejection rate? or is the 550mL the biggest one I can get for my 75GPD unit?
Question by: Stephen Balsano on Oct 29, 2017, 4:24 AM
You could try a larger flow restrictor, but honestly we would suggest giving a precision needle valve a try. For systems that need to be tuned the needle valve is the best value, instead of trying a bunch of different restrictors. Just replace your current flow restrictor with the one in the link below, and it does take a little bit of time and patience, but tuning them is pretty simple. Just slowly start closing the needle valve. You will see your water pressure react to the changes too, and by monitoring your TDS meter and pressure gauge, you should be able to find the best restriction point for your specific water.
Answer by: Charlie on Nov 18, 2017, 7:10 AM
Ok i give i have been looking for an hour and cant find any info on how to install this. Would have been nice if it would have been included in the shipment. Does it go on the waste water?
I have better more important things to do than waste an hour on this. What a joke!
Question by: Ag on May 25, 2016, 5:16 PM
Hey there,
The Membrane flush will be installed on the black waster water line exiting the membrane. This contains the flow restrictor and flush valve all in one and will be the only item on the black waste water line before the water enters the drain.
Answer by: Connor on May 25, 2016, 5:25 PM
Hello, I have a 24GPD older Kent unit. Can use the smallest of the valves to flush this unit?

Question by: bill on May 22, 2016, 3:27 PM
Great question! The 400ml flush valve will work great!
Answer by: Carter on May 25, 2016, 2:38 PM
My output runs to a storage container in the garage. When in flush mode does water exit the output line? If so is this bad water? Thinking of adding this to an existing RO/DI system that does not have it, and I really like your inline design integrated with the flow restrictor that exits to the drain line of the sink.

Also what size would be appropriate for a unit that has a 120 GPD membrane?

Question by: Alan on Apr 8, 2016, 10:49 AM
Great question!
When in flush mode a small amount of product water will still trickle out however most of the water will bypass and be sent down the waste water line. The 600 mL model will send more water to the RO membrane producing more water of slightly less quality, the 800 mL version will send more water down the waste and produce slightly cleaner water. Feel free to let us know if you have any further questions!
Answer by: Connor on Apr 13, 2016, 4:58 PM
I have the 75 GPD 5 stage + RO/DI unit and I am adding the BRS 150 GPD Water Saver Upgrade Kit. What is the correct size membrane flush valve I need for my system with the addition of the extra membrane?
Question by: Rick on Mar 7, 2016, 8:58 PM
That's a great question! You will continue to use the same 550mL flush valve/flow restrictor that you would with the single membrane, so no need to purchase anything new!
Answer by: Zack Wilson on Mar 10, 2016, 1:54 PM