Flow restrictors are essential to a properly functioning RO system. Be sure to have the appropriate flow restrictor for the membrane you have. If you decide to change your membrane to a higher or lower GPD membrane, you must also replace the flow restrictor to correspond with the membrane.
All BRS Reverse Osmosis Systems have the appropriate flow restrictor installed.
The 75 and 100GPD flow restrictors are barrel models. The 150GPD is a capillary flow restrictor, which is the stem style that goes inside of your RO units waste water line, and can be trimmed if desired for optimal results.
| Restrictor | Restrictor Style | Suggested RO Membrane |
| 200 mL | Barrel | 20-30 GPD |
| 300 mL | Barrel | 30-40 GPD |
| 350 mL | Barrel | 40-55 GPD |
| 550 mL | Barrel | 55-75 GPD |
| 800 mL | Barrel | 75-100 GPD |
| 800 mL | Capilary | 100-150 GPD |
| SKU | Reverse Osmosis Flow Restrictor |
|---|---|
| Aquarium Type | Saltwater, Freshwater |
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Product Questions
Which flow restrictor do I use with the 150 gpd membrane?
Question by: clint on May 12, 2025, 7:50 PM
Great question! You can use the 800ml on this page, but I would strongly recommend one with a flush valve. You can find that at the link below.
https://www.bulkreefsupply.com/membrane-flush-valve.html
https://www.bulkreefsupply.com/membrane-flush-valve.html
Answer by: Emily B (BRS Staff) on May 16, 2025, 1:20 PM
Now that the 800 has been discontinued, what should I use for the 200gpd water saver system? I want to replace the restrictor when I replace the membranes, so what should I use in its place?
Question by: Eric Peterson on Apr 26, 2024, 8:10 PM
Hi there! You would want sku 208447
Answer by: Grace (BRS Staff) on May 2, 2024, 4:08 PM
If I add a booster pump to a 5 stage system, using one 75 GPD membrane, do I need to change my restrictor size?
Question by: Conner Hein on May 26, 2023, 10:30 PM
No, you would not!
Answer by: Ash (BRS Staff) on Jun 2, 2023, 2:59 PM
How often (if ever) does a flow restrictor need to be replaced or cleaned?
Question by: Tim Piedimonte on Apr 24, 2023, 6:05 PM
Hey there,
We like to recommend that the flow restrictor be replaced with every change of the membrane. Thanks!
We like to recommend that the flow restrictor be replaced with every change of the membrane. Thanks!
Answer by: Codey on Apr 27, 2023, 2:57 PM
I've been checking out the you tube videos on how to upgrade r.o. systems.. I recently purchased a 50gpd aquatic life 3 stage system and aquatic life booster pump. If I purchase a 50 gpd membrane and housing and add that to the exsisting kit what restrictor should I purchase.?
Question by: jason on Apr 10, 2016, 7:58 PM
Great question!
If you were to find another 50 GPD membrane you will not need to change the flow restrictor. The same flow restrictor will be used on the single waste water line coming out of the second membrane. Feel free to let us know if you have any further questions!
If you were to find another 50 GPD membrane you will not need to change the flow restrictor. The same flow restrictor will be used on the single waste water line coming out of the second membrane. Feel free to let us know if you have any further questions!
Answer by: Connor on Apr 14, 2016, 10:29 AM
Is The 550 restrictor for 75gpd? I have a dual 75gpd membrane system with a 550 restictor. Just wanted to make sure it had the right restrictor. Thanks
Question by: Joey on Jul 19, 2014, 1:09 PM
Hi Joey,
If you have 75gpd membranes then the 550 would be the correct flow restrictor :)
If you have 75gpd membranes then the 550 would be the correct flow restrictor :)
Answer by: Bulk Reef Supply on Jul 19, 2014, 1:09 PM
I bought a used 75gpd unit of yours from a friend. He didn't have the restrictor and I have a spare 100gpd membrane. If I purchase the restrictor for a 100gpd unit can I use my membrane and produce 100gpd?
Question by: Ryan on Jun 17, 2014, 2:25 PM
Hi Ryan,
As long as you change the flow restrictor to the 100gpd to match your 100gpd unit, you can run the 100gpd membrane.
As long as you change the flow restrictor to the 100gpd to match your 100gpd unit, you can run the 100gpd membrane.
Answer by: Bulk Reef Supply on Jun 17, 2014, 2:25 PM
Which line do I connect the flow restrict or to? I bought the R/O unit used, replaced all the filters including the membrane. The unit did not have a restrictor on it...
Question by: Mike on Apr 8, 2014, 11:16 AM
Hi Mike,
The flow restrictor always goes on the waste water line. They come in a few different varieties including some that are on the inside of the tubing. Your unit likely wouldn't have worked without one so pretty good bet its hiding there somewhere.
The flow restrictor always goes on the waste water line. They come in a few different varieties including some that are on the inside of the tubing. Your unit likely wouldn't have worked without one so pretty good bet its hiding there somewhere.
Answer by: Bulk Reef Supply on Apr 8, 2014, 11:16 AM
i bought your 150 gpd water saver upgrade kit should i change my 75 gal flow restrictor to the 150 flow restrictor
Question by: John on Nov 24, 2013, 10:44 AM
Hi John,
No you should not. You want to keep your existing 75gpd flow restrictor :-)
No you should not. You want to keep your existing 75gpd flow restrictor :-)
Answer by: Bulk Reef Supply on Nov 24, 2013, 10:44 AM
Where do you install the flow restrictor? Does it go on the incoming water to the membrane or the out going side?
Question by: Thomas on Oct 23, 2013, 1:46 AM
Hey Thomas,
It goes on the waste water line out of the membrane.
It goes on the waste water line out of the membrane.
Answer by: Bulk Reef Supply on Oct 23, 2013, 1:46 AM
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