Reverse Osmosis

Ensure the best water quality for your reef tank with our reverse osmosis deionization systems (RO/DI Systems). We take pride in offering well-built, leak-free systems that are both affordable and durable. With high-quality filters from trusted brands like GE and DOW, and robust dual O-ring push connect fittings, our systems deliver premium performance. Hand-built in Minnesota, our Bulk Reef Supply RO and RO/DI systems come in various configurations to meet your exact needs.

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What is RO/DI?

RO/DI stands for Reverse Osmosis Deionization, which is just a fancy name for a specific method of water filtration.

What does an RO/DI System do?

An RO/DI system removes contaminants from tap water, making it safe for use in your aquarium. RO and RO/DI systems are almost identical except the RO/DI system has an extra deionization (DI) filtration stage that brings the water down to 0 TDS (total dissolved solids).

Do I really need an RO/DI system?

If you're keeping a saltwater aquarium, RO/DI water is simply the best foundation to start with.

Tap and well water more often than not contains a whole host of unwanted contaminants and impurities that we simply don't want in our aquariums. Some will cause issues right away, while others silently build up over time.

By starting with the best water possible, we remove that variable from the equation entirely.

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How It Works

Reverse osmosis systems purify water by passing it through multiple filtration stages that each have specific roles in removing contaminants before the water reaches your storage container.

Explore the process in detail →
1 Sediment Filter

Removes particles like dirt, rust, and sand.

2 Carbon Block

Reduces chlorine, chloramines, odor, and some chemical contaminants.

3 RO Membrane

Core of the system, removing up to 99% of dissolved solids.

4 DI Resin

Final filtration stage, polishing water down to 0 TDS.

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No Plumbing Experience Required

Setting up a BRS RO/DI system is easy. If you can connect a garden hose to your spigot, you can install an RO system.

Common connection methods include:

Garden Hose / Utility Sink Adapter
Connect your RO system directly to a standard garden hose or utility sink thread. This option is great for dedicated mixing stations, laundry rooms, garages, or outdoor use.

Faucet Diverter Valve
The faucet diverter valve allows you to temporarily connect the RO system to most kitchen or bathroom faucets. With the turn of a lever, you can switch between normal faucet use and supplying water to the RO system.


Easy Setup Guides:

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How often do I need to replace the filters?

Filter replacement depends on how much water you make, your source water quality, and the contaminants you're trying to remove, but here are some good rules of thumb:

Sediment Filter

Replace when pressure starts to drop. A clogged sediment filter restricts water pressure causing poor RO membrane performance and slower water filtration.

Carbon Block

Replace on a regular schedule, usually every 6 to 12 months.

Choose every 6 months if your water contains chloramines or you make a lot of RO/DI water.

RO Membrane

Usually lasts 3+ years when pre-filters are maintained properly.

Check performance by comparing incoming TDS to post-membrane TDS. With most membranes, you should see a TDS reduction approaching 99% under ideal conditions.

DI Resin

Replace when final TDS rises above 0.

If you use color-changing resin, replace it before the color change reaches the top of the cartridge.


Filter Replacement Resources:

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How often do I need to replace the filters?

Filter replacement depends on how much water you make, your source water quality, and the contaminants you're trying to remove, but here are some good rules of thumb:

Sediment Filter

Replace when pressure starts to drop. A clogged sediment filter restricts water pressure causing poor RO membrane performance and slower water filtration.

Carbon Block

Replace on a regular schedule, usually every 6 to 12 months.

Choose every 6 months if your water contains chloramines or you make a lot of RO/DI water.

RO Membrane

Usually lasts 3+ years when pre-filters are maintained properly.

Check performance by comparing incoming TDS to post-membrane TDS. With most membranes, you should see a TDS reduction approaching 99% under ideal conditions.

DI Resin

Replace when final TDS rises above 0.

If you use color-changing resin, replace it before the color change reaches the top of the cartridge.


Filter Replacement Resources:

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BRS System Comparison Chart

Feature 4 Stage RO Only 4 Stage Value 4 Stage Value Plus 5 Stage Premium 5 Stage Premium Plus 6 Stage Deluxe Plus 7 Stage PRO Plus
Production Rate Options 75 GPD 75 / 100 / 150 GPD 75 / 100 / 150 / 200 GPD 75 / 150 / 200 GPD 75 / 100 / 150 / 200 GPD 75 / 100 / 150 / 200 GPD 75 / 150 / 200 GPD
Makes 0 TDS Water
Sediment Filter
Carbon Block Filter ✅✅ ✅✅ ✅✅ ✅✅ ✅✅
RO Membrane
Mixed Bed DI Resin ✅✅ ✅✅ ✅✅
Separate Cation / Anion DI Stages ✅✅
Chlorine Filtration Better Good Good Best Best Best Best
Chloramine Filtration Basic Best Best Best Best
Pressure Gauge
Manual Flush Valve
Inline TDS Meter Dual Dual Dual Triple

Note: The 4 Stage RO Only system does not include DI resin, so it is not designed to produce 0 TDS water out of the box. For reef aquariums, most hobbyists use an RO/DI system because the DI stage polishes the water after the RO membrane.

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205 Items

  1. 3 Stage 75 GPD AquaReady RO System
    AquaReady
    3 Stage 75 GPD AquaReady RO System
    $69.99 $69.99

  2. 7 Stage Universal RO/DI Replacement Filter Kit
    Bulk Reef Supply
    7 Stage Universal RO/DI Replacement Filter Kit
    $61.19 $76.49

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  3. 6 Stage Universal RO/DI Replacement Filter Kit
    Bulk Reef Supply
    6 Stage Universal RO/DI Replacement Filter Kit
    $50.39 $62.99

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  4. 4 Stage Universal RO/DI Replacement Filter Kit
    Bulk Reef Supply
    4 Stage Universal RO/DI Replacement Filter Kit
    $24.47 $30.59

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  5. 5 Stage Universal RO/DI Replacement Filter Kit
    Bulk Reef Supply
    5 Stage Universal RO/DI Replacement Filter Kit
    $39.59 $49.49

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  6. 5 Stage Premium Plus 75 GPD RO/DI System
    Bulk Reef Supply
    5 Stage Premium Plus 75 GPD RO/DI System
    $194.39 $242.99

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  7. 5 Stage Premium 75 GPD RO/DI System
    Bulk Reef Supply
    5 Stage Premium 75 GPD RO/DI System
    $179.99 $224.99

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  8. 5 Stage Premium Plus 100 GPD RO/DI System
    Bulk Reef Supply
    5 Stage Premium Plus 100 GPD RO/DI System
    $237.59 $296.99

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  9. 5 Stage Premium 200 GPD Water Saver RO/DI System
    Bulk Reef Supply
    5 Stage Premium 200 GPD Water Saver RO/DI System
    $244.79 $305.99

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  10. 5 Stage Premium 150 GPD Water Saver RO/DI System
    Bulk Reef Supply
    5 Stage Premium 150 GPD Water Saver RO/DI System
    $230.39 $287.99

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  11. 6 Stage 75GPD Drinking & Reef RO/DI System with Brushed Nickel Faucet
    Bulk Reef Supply
    6 Stage 75GPD Drinking & Reef RO/DI System with Brushed Nickel Faucet
    $251.99 $314.99

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  12. 6 Stage 75GPD Drinking & Reef RO/DI System with Silver Faucet
    Bulk Reef Supply
    6 Stage 75GPD Drinking & Reef RO/DI System with Silver Faucet
    $251.99 $314.99

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  13. 5 Stage Premium Plus 200 GPD Water Saver RO/DI System
    Bulk Reef Supply
    5 Stage Premium Plus 200 GPD Water Saver RO/DI System
    $287.99 $359.99

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  14. 5 Stage Premium Plus 150 GPD Water Saver RO/DI System
    Bulk Reef Supply
    5 Stage Premium Plus 150 GPD Water Saver RO/DI System
    $251.99 $314.99

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  15. 5 Stage 75GPD Drinking Water RO System with Nickel Faucet
    Bulk Reef Supply
    5 Stage 75GPD Drinking Water RO System with Nickel Faucet
    $223.19 $278.99

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  16. 5 Stage 75GPD Drinking Water RO System with Silver Faucet
    Bulk Reef Supply
    5 Stage 75GPD Drinking Water RO System with Silver Faucet
    $223.19 $278.99

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  17. 4 Stage Value 75GPD RO/DI System
    Bulk Reef Supply
    4 Stage Value 75GPD RO/DI System
    $143.99 $179.99

  18. 4 Stage Value Plus 200GPD Water Saver RO/DI System
    Bulk Reef Supply
    4 Stage Value Plus 200GPD Water Saver RO/DI System
    $251.99 $314.99

  19. 4 Stage Value Plus 150GPD Water Saver RO/DI System
    Bulk Reef Supply
    4 Stage Value Plus 150GPD Water Saver RO/DI System
    $237.59 $296.99

  20. 4 Stage Value Plus 75GPD RO/DI System
    Bulk Reef Supply
    4 Stage Value Plus 75GPD RO/DI System
    $179.99 $224.99

  21. 4 Stage Value Plus 100GPD RO/DI System
    Bulk Reef Supply
    4 Stage Value Plus 100GPD RO/DI System
    $223.19 $278.99

  22. BRS 4 Stage RO Only System - 75GPD
    Bulk Reef Supply
    BRS 4 Stage RO Only System - 75GPD
    $129.59 $161.99

  23. 4 Stage Value 100GPD RO/DI System
    Bulk Reef Supply
    4 Stage Value 100GPD RO/DI System
    $151.19 $188.99

  24. 4 Stage Value 150GPD Water Saver RO/DI System
    Bulk Reef Supply
    4 Stage Value 150GPD Water Saver RO/DI System
    $194.39 $242.99

  25. BRS 4 Stage RO Only Replacement Filter Kit
    Bulk Reef Supply
    BRS 4 Stage RO Only Replacement Filter Kit
    $23.75 $29.69

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  26. 4 Stage RO/DI Replacement Filter Kit
    Bulk Reef Supply
    4 Stage RO/DI Replacement Filter Kit
    $20.87 $26.09

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  27. Kleanwater 4 Stage Basic RO Filter Kit
    Bulk Reef Supply
    Kleanwater 4 Stage Basic RO Filter Kit
    $26.63 $33.29

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  28. Max Silica Removal Filter Kit (for MaxCap Systems)
    Bulk Reef Supply
    Max Silica Removal Filter Kit (for MaxCap Systems)
    $37.43 $46.79

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  29. Matrikx 5 Stage RO/DI Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 5 Stage RO/DI Replacement Filter Kit
    $30.23 $37.79

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  30. Matrikx 4 Stage RO (no DI) Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 4 Stage RO (no DI) Replacement Filter Kit
    $20.22 $23.79

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  31. Matrikx 7 Stage Pro RO/DI Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 7 Stage Pro RO/DI Replacement Filter Kit
    $53.27 $66.59

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  32. Matrikx 4 Stage RO Drinking Water Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 4 Stage RO Drinking Water Replacement Filter Kit
    $32.97 $38.79

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  33. Kleanwater 4 Stage Upgrade Filter Kit - With Refillable DI
    Bulk Reef Supply
    Kleanwater 4 Stage Upgrade Filter Kit - With Refillable DI
    $32.39 $40.49

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  34. AquaMaxx 4 Stage Upgrade Filter Kit - With Refillable DI
    Bulk Reef Supply
    AquaMaxx 4 Stage Upgrade Filter Kit - With Refillable DI
    $31.67 $39.59

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  35. Kleanwater 6 Stage Upgrade Filter Kit - With Refillable DI
    Bulk Reef Supply
    Kleanwater 6 Stage Upgrade Filter Kit - With Refillable DI
    $62.63 $78.29

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  36. Matrikx 6 Stage RO/DI Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 6 Stage RO/DI Replacement Filter Kit
    $41.03 $51.29

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  37. Matrikx 4 Stage RO/DI Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 4 Stage RO/DI Replacement Filter Kit
    $20.15 $25.19

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  38. Matrikx 5 Stage Drinking & Reef RO/DI Replacement Filter Kit
    Bulk Reef Supply
    Matrikx 5 Stage Drinking & Reef RO/DI Replacement Filter Kit
    $36.71 $45.89

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  39. 7 Stage Pro RO/DI Replacement Filter Kit
    Bulk Reef Supply
    7 Stage Pro RO/DI Replacement Filter Kit
    $64.79 $80.99

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  40. 6 Stage RO/DI Replacement Filter Kit
    Bulk Reef Supply
    6 Stage RO/DI Replacement Filter Kit
    $53.99 $67.49

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