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Reverse Osmosis

(40 items)
Any aquarium owner looking to produce perfect water conditions for their fish and coral ought to get started with reverse osmosis water. The chlorine and chloramines that are poisonous to fish are totally absent from RO water, which also has a pH that is neutral and no water hardness. To flourish, many tropical fish need particular types of aquatic habitats, and RO systems can be your key to creating those conditions in your tank.

Top RODI Filter Picks

A table comparing the facets of 4 items
Facet
Seahorse 4-Stage Compact RO/DI System - AquaFX
Seahorse 4-Stage Compact RO/DI System - AquaFX
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Barracuda RODI Unit - Standard 100 GPD - AquaFX
Barracuda RODI Unit - Standard 100 GPD - AquaFX
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Barracuda RODI Unit - Glacial 100 GPD - AquaFX
Barracuda RODI Unit - Glacial 100 GPD - AquaFX
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Barracuda RODI Unit - Glacial 100 GPD (Chloramines Upgraded) - AquaFX
Barracuda RODI Unit - Glacial 100 GPD (Chloramines Upgraded) - AquaFX
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ByAquaFXAquaFXAquaFXAquaFX
Price
Price
$8499
$19999
$27999
$32999
Description
Description
- Compact, portable 4-stage RO/DI system (50–100 GPD)

- Hand-built in the USA, affordable + space-saving

- Zero TDS water; removes heavy metals, chlorine, lead, more

- Easy-change translucent DI cartridge for monitoring

- Quick-disconnect fittings; includes tubing + garden hose adapter
- Heavy-duty 4-stage RO/DI system, 100 GPD output

- Hand-built in the USA; 0 TDS, phosphate-free water

- 1-micron sediment + chlorine carbon block pre-filters

- Color-indicating DI resin; pressure gauge included

- Aluminum mounting bracket + filter wrench; ready to install
- Same top-tier 4-stage Barracuda system, 100 GPD

- Designed for ultra-pure reef + top-off water

- Upgraded carbon options to handle chlorine or chloramines

- Color-change DI resin, pressure gauge, quick-connect fittings

- Durable aluminum mount; includes hoses + filter wrench
- Premium 4-stage RO/DI with chloramines-focused upgrade

- Built in the USA for ultra-pure 0 TDS aquarium water

- Special carbon block pre-filter to remove chloramines

- Color-indicating DI resin; pressure gauge + heavy-duty bracket

- Complete kit: filter wrench, hose adapter, tubing included

Dive Deeper: Info & Tips for Reverse Osmosis

When it comes to reef tanks, water quality is everything — and the best place to start is with a reliable reverse osmosis system. Tap water often contains chlorine, chloramines, heavy metals, and other impurities that can harm sensitive livestock and fuel unwanted algae growth. A high-quality RODI (Reverse Osmosis Deionization) unit strips out these contaminants, giving you a clean slate before any salt mix or additives are introduced.

At Top Shelf Aquatics, we carry RODI systems built specifically for reef keepers. Whether you're topping off evaporation or mixing water for a full change, a dependable RO system helps ensure long-term stability and success. From compact 4-stage units to advanced multi-stage setups with pressure gauges and flush valves, there's an option for every level of tank maintenance.

Choosing the Right Reverse Osmosis System

  • 4-Stage RODI Systems
    These units are a great choice for hobbyists who need effective filtration without overcomplication. The stages typically include a sediment filter, carbon block, RO membrane, and a deionization (DI) resin cartridge. They’re well-suited for small to mid-sized reef tanks and provide a solid balance of purity and affordability.
  • 5-Stage RODI Systems
    A 5-stage system adds an extra carbon block or DI stage for more thorough filtration, offering greater peace of mind when it comes to removing chloramines, silicates, and other tough contaminants. If your local tap water is heavily treated or you’re running a larger tank, this upgrade is often worth it for the added security and cleaner water.

Optimizing RODI System Performance

Even the best RODI system needs proper care and setup to function at its peak. Here are a few key tips to help you get the most out of your unit:

  • Monitor TDS Output Regularly
    Use an inline or handheld TDS (total dissolved solids) meter to track water quality. Your system should produce water with a TDS reading of 0. If it creeps above that, it’s time to check the DI resin or RO membrane.

  • Flush the Membrane Periodically
    Many 5-stage systems come with a manual flush valve or auto-flush feature. Flushing the RO membrane helps clear out trapped particles and prolongs its lifespan, especially in areas with hard water.

  • Change Filters on Schedule
    Sediment and carbon filters should typically be replaced every 6 months, or sooner if your water pressure drops or chlorine gets past the carbon stage. The DI resin and RO membrane have longer lifespans but should be swapped as needed based on TDS readings.

  • Install in a Well-Ventilated Area
    Heat and humidity can affect filter performance and encourage bacterial growth in stagnant water. A cool, dry place like a garage or utility closet is ideal for mounting your system.

  • Use a Float Valve or Auto Shut-Off
    Prevent accidental overflows by pairing your RODI system with a float valve or shut-off kit. These small additions add a layer of safety and save water.

Expert Tips

  • Label Your Filter Change Dates
    Mark the date of installation directly on each cartridge with a sharpie or sticker. This makes it easy to remember when your next swap is due and helps you stay ahead of declining performance.

  • Keep Spare Filters on Hand
    Don’t wait until your TDS spikes or filters clog to place a reorder. Having an extra sediment filter or DI resin cartridge ready means less downtime and more stability for your tank.

  • Flush New Carbon Blocks Before Use
    When installing a new carbon filter, flush the system for a few minutes before collecting water. This removes carbon dust that can otherwise clog your RO membrane or tint the DI resin prematurely.

  • Pair with a Reservoir and Float Valve
    Running your RODI line to a clean water reservoir with a float valve ensures a steady supply for top-off systems and salt mixing. It also protects against accidental overflows.

  • Use Cold Tap Water for Efficiency
    RODI membranes perform best around 77°F. While you don’t need to pre-chill your water, avoid hot water lines — they can damage the membrane and reduce rejection rates.

Installation & Maintenance

Installation Tips
Most RODI systems are designed to install under a sink, in a garage, or near a utility sink. You’ll typically connect it to a cold water source using an adapter or faucet diverter, then run the output line to a clean container or reservoir. Always follow the included flow direction labels to ensure water passes through each stage correctly.

If your system comes with a bracket, wall-mounting it near your water source can save space and keep everything organized. Just be sure to allow room to change cartridges when needed.

Routine Maintenance

  • Sediment & Carbon Filters: Replace every 6 months, or sooner if pressure drops or chlorine is detected in the RO stage.

  • DI Resin: Replace when TDS starts to rise above zero from the DI stage.
  • RO Membrane: Replace approximately every 2–3 years, or as needed depending on water quality and usage.
  • Flush Valve (if applicable): Use regularly to prolong membrane life and maintain performance.
  • TDS Meter Readings: Monitor before and after the DI stage to catch issues early.

Routine care ensures your system continues to produce clean, reef-safe water and protects your livestock from the hidden risks found in untreated tap water.

Top RODI Filter Picks

What’s the difference between RO and RODI?

RO (Reverse Osmosis) removes most contaminants, but not all. The DI (Deionization) stage polishes the water by removing remaining ions like nitrates, phosphates, and silicates — giving you 0 TDS water, ideal for reef tanks.

How do I know when to change the filters?

You’ll typically want to change sediment and carbon filters every 6 months. Use a TDS meter to monitor DI resin and RO membrane performance. When TDS rises above 0, it’s time to replace those stages.

Can I use well water with a RODI system?

Yes, but it depends on your well water's composition. High iron, sulfur, or sediment levels can clog filters quickly. You may need pre-filtration to protect the system and extend filter life.

What size RODI system should I get?

For most reef tanks, a 4-stage or 5-stage system is more than enough. Larger tanks or homes with poor tap water may benefit from the added filtration in a 5-stage setup.

Do I need to flush the system before using the water?

When first installing or after changing filters, yes. Flush the system for a few minutes to clear out dust and packing residue. After that, you can use the water as normal.