Bulk Reef Supply

4 Stage Value 75GPD RO/DI System

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BRS 4 Stage Systems are perfect for reefers who have water treated with chlorine or relatively clean well water. The 4 stage systems are self-contained on a single bracket making them ideal for tight spaces or where a non-permanent connection may be required. Installing a RO/DI system only takes a few minutes and can be done very easily without any permanent modifications to your home or the plumbing.

4 Stage Value RO/DI Features:

  • Multiple source water connections
  • Mur-lok Push Connect dual EPDM O-Ring fittings
  • 10 Ft Each of 1/4" Blue, Red and Black Tubing
  • Pre-installed NSF Certified Filters NSF Certified


Lifetime Warranty All Bulk Reef Supply RO/DI Systems are covered by our Limited Lifetime Warranty.


Bulk Reef Supply RO/DI systems only use the latest filters and components in Reverse Osmosis technology. We have designed our RO/DI units especially for reef tanks, but they can produce perfect water for other types of saltwater and freshwater aquariums too. If you have a well, or you are connected to city water we provide a variety of RO/DI systems that will fit your aquarium's needs.


4 Stage RO/DI Systems - Perfect for city water that is treated with low amounts of chlorine, or well water with very minimal contaminants.
5 Stage RO/DI Systems - Our most popular system handles most types of well water along with most types of city water treated with chlorine including small amounts of chloramines.
6 Stage RO/DI Systems - If you are not sure what is in your water, or it contains excessive amounts of TDS or hard to remove contaminants like chloramines, phosphates, nitrates, silicates, etc. The BRS 6 Stage systems are designed to treat any water your home may have effectively. The Dual DI stage helps with the hard to remove ions like ammonia, phosphates, silicates, etc.


4 Stages of Filtration

Stage 1

Purtrex 5 Micron Depth Sediment Filter NSF Certified

Sediment filters trap debris and other free-floating particles that would normally clog expensive carbon blocks and foul membranes. Purtrex filters are a true depth filter with a graded density that progressively gets tighter through as water passes through the filter allowing them to last longer than the competitors.

Stage 2

BRS 5 Micron VOC Block NSF Certified (Chlorine 15,000 @ 1 GPM)

Our VOC carbon blocks are specially formulated to remove and reduce chlorine and volatile organic compounds from household water.

Stage 3

75 GPD Dow Filmtec MembraneNSF Certified (up to 99% rejection rate*)

DOW is hands down the industry leader for residential RO membranes. The 75 GPD Filmtec membrane can remove up to 99% of contaminants from traditional household drinking water. All membranes do require pressure to operate correctly, and DOW's membrane only requires 50 PSI of feed pressure to operate efficiently. For more info on DOW membranes - Click Here

Stage 4

Nuclear Grade Color-Changing Deionization Resin

Deionization resin is the final stage of the RODI system and will polish your water down to 0 TDS. The DI resin is a mixed bed with a color changing indicator to let you know when it is becoming depleted. The resin starts as a dark blue color that will turn gold when as it becomes exhausted and is a good indicator to let you know when to it should be replaced.
For more info on Color Changing DI Resin - Click Here


Need Replacement Filters? 4 Stage Chlorine/VOC Filter Kit


BRS RO/DI 4 Stage System Comparison

  BRS 4 Value RO/DI Systems BRS 4 Value Plus RO/DI Systems
Gallons Per Day
75, 100, 150, or 200
75, 100, 150, or 200
Sediment Filter
Purtrex 5 Micron Depth Sediment Filter 
Purtrex 5 Micron Depth Sediment Filter 
Carbon Block
BRS VOC 5 Micron Carbon Block 
BRS VOC 5 Micron Carbon Block  
75 or 100 GPD Dow Filmtec Membrane

75 or 100 GPD Dow Filmtec Membrane

Single Mixed Bed DI Stage with Refillable Cartridge

Single Mixed Bed DI Stage with Refillable Cartridge

Auto Shut Off Valve
Canister Wrench
Laundry Tub Connection Adapter
Chrome Faucet Diverter Valve
Glycerin Filled Pressure Gauge  

Flush Kit  
Dual Inline TDS Meter  
Dimensions 16" x 6.25" x 15.5" 16" x 7" x 15.5"


4 Stage Value RO/DI System Recommended Conditions:

  • Minimum Water Pressure - 50 PSI
  • Max Water Pressure - 90 PSI
  • Recommended Water Temperature - 77°F
  • Recommended Max TDS - <300ppm

Water pressure can be increased by adding a booster pump before your RO/DI system if a pressure increase is required. Low pressure will cause slow production of product water, with excess production of waste water. Pressure over 90 PSI may cause damage to the RO/DI units filters and components.


*DOW Filmtec 75 GPD Membranes have a 96% - 99% typical stabilized salt rejection rate that can be reproduced through the following conditions;

  • Source Water Pressure - 50 PSI / Membrane
  • Source Water Temperature - 77°F
  • Source Water TDS - 250ppm Softened Tap Water
  • Recovery - 15%
  • Minimum Salt Rejection - 96%

For more info on DOW Filmtec BW60-1812-75 Membrane - Click Here


pdf BRS 4 Stage Value RO/DI System Instructions

pdf Dow Filmtec Membrane BW60-1812-75

More Information
UPC 853710007735
Stages 4 Stage
Production Rate 75 Gallons per Day
Waste:Product Water Standard (3:1)
Dimensions 16" x 6.25" x 15.5"
Filter Dimensions 10 in. x 2.5 in. (Standard)
Tubing Length 10 ft
Included Filters Sediment Filter, Carbon Block, RO Membrane, DI Resin (Mixed Bed)
Additional Notes Rejection Rate: 96-99%
Recommended conditions:
  • Min. Water Pressure: 50 PSI
  • Max. Water Pressure: 90 PSI
  • Water Temperature: 77°F
  • Max. TDS - <300ppm
Carbon Block Type Chlorine
Sediment Filter Type True Gradient Technology
Membrane GPD 75
Micron Rating 5
Resin Type Color Changing
Water Supply Connections Faucet Diverter Valves, Garden Hose / Laundry Tub
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Product Questions

What else must I purchase to complete the installation of this ROI system? Thanks
Question by: Bruce Olitzky on Jan 20, 2023, 9:17 PM
HEy Bruce, thanks for reaching out to us! These come ready to run! The only thing you might consider is a float valve to install in the reservoire you are filling as well as a different source water connection other that the one we give you!
Answer by: James Johnson (BRS Staff) on Feb 9, 2023, 2:00 PM
Does this unit have the option to temporarily remove the DI filter from the system and use the RO part as a drinking water purifier when I'm not using it for my tank?
Question by: Samaya on Jul 1, 2022, 5:20 PM
Thanks for the question! There are two ways to do this, the first is to put a T on the blue line between the RO membrane and the DI and opening or closing the valve to direct the water, the other is to simply unscrew the canister and remove the internal DI cartridge. The second option should only be used for a short period to keep the DI resin from drying out though. Let us know if we can help with anything else!
Answer by: Kyle Thomas (BRS Staff) on Jul 6, 2022, 10:51 AM
Does this come with a check valve pre installed? Want to connect to a float switch and need to know what else i need besides a float switch/
Question by: Chris Wong on May 23, 2022, 5:28 PM
Hey there,
Thank you for reaching out to us. Unfortunately, this does not have a check valve pre-installed.

Please let me know if you need anything further and take care!
Answer by: Matt Lucero (BRS Staff) on May 24, 2022, 10:47 AM
How many gallons waste to every gallon of RO?
Question by: Brad Perkons on Jan 29, 2018, 7:51 PM
It has a 4:1 waste to product water ratio.
Answer by: Charlie on Jan 30, 2018, 4:45 AM
Is a ro di system a must to have a saltwater tank?
Question by: Mitchell Wong on Nov 24, 2017, 7:03 PM
We do highly recommend a RODI unit for a saltwater aquarium. Almost all local fish stores will have RO water for sale, but over time hauling pails or jugs of water back and forth can become a task and troublesome. If you ask 10 reefers what is the best purchase they ever made for their saltwater tank, about half would say their RODI system.
Answer by: Charlie on Nov 25, 2017, 8:32 AM
I have a 36 gallon mixed reef tank and live in central florida with limestone and well water. Would this or one of the other rodi systems be appropriate? Is the 4 stage correct?
Question by: John on Nov 18, 2017, 12:33 PM
The 4 stage RODI system would be a good choice for your water. A majority of the lime will be removed by the membrane, so the additional carbon block won't be much of a performance increaser. However, if your city uses chlorine or chloramines, then we would suggest a 5 stage reverse osmosis system or even a 6 stage if chloramines are being used.
Answer by: Charlie on Nov 18, 2017, 6:53 PM