7 Stage PRO Plus 75 GPD 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.

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.

The star of the show is the RO membrane. Using your home's water pressure, purified water is pushed through the membrane while impurities are rejected into a separate waste-water tube.

Standard RO systems use three primary filtration stages to remove sediment, chemicals, and dissolved contaminants. RO/DI systems add a fourth stage of deionization resin that further purifies the water and acts as a final polish to ensure zero total dissolved solids (TDS).

While water quality can vary wildly from one source to the next, we've come up with some good rules of thumb for when each system makes sense.

Bulk Reef Supply RO/DI systems are designed with aquarium hobbyists in mind and are built with proven filtration components. Every system is carefully assembled and tested right here in Golden Valley, Minnesota so we can maintain strict quality control over every system we produce.

Unlike many generic RO systems, BRS systems use high-quality components, including premium RO membranes, refillable DI cartridges, and industry-leading carbon blocks designed to protect the membrane and extend system life. Double O-ring push connect fittings help ensure a tight seal and reduce the chances of leaks for added peace of mind.

BRS systems are also designed to be easy to monitor and maintain. The "Plus" models have built-in features like pressure gauges, flush valves, and TDS meters help you quickly verify that the system is operating properly and producing pure water for your aquarium.

Finally, every BRS RO/DI system is backed by a limited lifetime warranty, extensive educational resources, and knowledgeable support. From installation guides to troubleshooting help, the BRS team is here to make sure your system continues producing clean, reliable water for years to come.

Filter replacement depends on three main factors:

• How much water you're producing
• The quality of your source water
• The types of contaminants in that water

Here are a few simple ways to know when each stage needs attention:

Sediment Filter
As the sediment filter begins to clog with debris like rust, sand, and dirt, the pressure entering the RO membrane will start to drop. If your system has a pressure gauge, it's time to replace the sediment filter when you start seeing a decrease in pressure. If your system doesn't have a gauge, we recommend proactively changing out your sediment filter every 6-12 months or so

Carbon Block
Carbon filters are harder to monitor directly, so they are usually replaced on a schedule. Most hobbyists change them every 6 to 12 months. If your water supply contains chloramines or you produce large amounts of RO/DI water, replacing them closer to every 6 months is recommended.

RO Membrane
The RO membrane typically lasts around 3 years when the sediment and carbon filters are replaced regularly. You can also monitor performance by comparing the TDS of the incoming water to the TDS after the membrane. Most membranes reject about 98% of dissolved solids. For example, if the incoming water measures 100 TDS, the water leaving the membrane should be close to 2 TDS.

DI Resin
This is the final stage that brings your water down to 0 TDS. If the water leaving the system reads above 0 TDS, the resin is exhausted and should be replaced. If you do not have a TDS meter, color-changing DI resin provides a visual indicator. Replace the resin just before the color change reaches the top of the cartridge.

You can install your RO or RO/DI system outdoors, but it should be in a covered location out of the elements. Avoid placing it in an area that receives direct sunlight as it can cause algae to grow inside the canisters. TDS meters on Plus models are NOT waterproof.

Note: Bring your RO system inside if temperatures will drop below freezing. If water inside the canisters is allowed to freeze, this will cause the canisters to burst.

Waste water is a normal part of the RO filtration process, but if you're looking to put the water to good use, we often use it to water our plants!

Low water pressure won't damage the RO system, but it will reduce performance and result in lower than advertised daily water production. If your home's water pressure is low, consider adding a booster pump.

Learn More: How to Install a Booster Pump on an RO/DI System

Yes, however we typically use RO filtration only for drinking water, not RO/DI. You'll want to install a tee fitting after the RO membrane and before the DI resin so you can switch between making RO/DI water for your aquarium and RO water for drinking.

If you're looking for an RO system exclusively for drinking water, check out our BRS Drinking Water RO Systems.

Yes, this is completely normal.

Because water will flow through the DI cartridge from the bottom to the top, it's normal for some air to get trapped in the canister. This is normal and does not affect the quality of water being produced. In fact, air trapped in the DI stage is an indication of a good seal between the DI cartridge and the top of the canister housing.