The Benefits of Reverse Osmosis Water

Reverse Osmosis, commonly referred to as RO, is a process where you demineralize or deionize water by pushing it under pressure through a semi-permeable Reverse Osmosis Membrane. Many marine and freshwater fish keepers use reverse osmosis (RO) to produce high quality water as the membrane traps and removes 90% to 99% of the impurities from the water. This process can remove many types of ions and impurities from water that you would harmful to a home aquarium.

Most of the reverse osmosis and de-ionization systems produce purified water by filtering the raw water in either 3 or 4 stages. The purified water can then be used in the aquarium, while the waste water which contains concentrated contaminants can be discarded or used for your garden plants.

Why not Tap Water or Rainwater?


Most tap water sources contain dissolved salts, nitrates and phosphates as per federal guidelines on city water treatment.  While this is safe for human consumption, it can be very unsafe for your aquarium. In fact, areas with excessively hard tap water will hurt the development of your soft water fish.

If your tap water contains even traces of phosphate, you are promoting algae growth every time you top off the tank. You may also deal with high chlorine and chloramine in tap water. Also, your tap water quality can change with the seasons, weather and chemical requirements which makes tap water inconsistent. This makes keeping a reef aquarium quite difficult.

Furthermore, it is too risky to use rainwater to fill your aquarium as cities with heavy air pollution will have more acidic rainwater with harmful pollutants. While some people still use rainwater, this can carry harmful pollutants that may endanger your fish. Thus, rainwater poses a problem for aquarium enthusiasts.

Why use Reverse Osmosis Water?

Reverse Osmosis water has several advantages over tap water. Unlike tap water, reverse osmosis water is much purer and is low in organics, dissolved minerals and nutrient compounds. This removes contaminants which promote the growth of nuisance algae. Using reverse osmosis water also removes the limitations of your local tap water so that you can maintain a range of fish from different aquatic environments.

Reverse osmosis water and de-ionization units are very popular among aquarists. Reverse Osmosis and de-ionization are different processes which are often done in conjunction with other filtration systems. When these two processes are combined, pure water is produced.

Bypass Purification Chemicals and Cleaning Filters


Some users resort to using purification chemicals and cleaning filters to remove dissolved salts and particles from their tap water. However, this is a costly method and it may be cheaper to purchase a reverse osmosis unit instead.

Some users use filters and chemicals to filter tap water. However, this alone may not make the water safe for use in aquariums. The unit, by itself, cannot remove chlorine and chloramine compounds used in tap water purification. This could adversely hurt the development of your fish which are sensitive to chlorine.

Whereas, in reverse osmosis, particles are removed by a fine sediment filter and passed through a carbon block to remove chlorine. The water is then passed through the reverse osmosis membrane and removes nitrates, silicates, phosphates, and other compounds. Lastly, in deionization, water is passed through the deionization resins which remove minerals and compounds. This produces pure water.

Stable Environment

General Pic

Most aquariums require a stable environment such as a constant pH and temperature. A stable environment is essential for a thriving aquarium. As fish and coral cannot survive drastic changes in pH and salinity, reverse osmosis water offers the best possible water quality and stable environment for your aquarium’s inhabitants.

Through re-mineralisation, reverse osmosis water can be retrofitted to fit any aquatic environment. With reverse osmosis water, any fish keeper can produce the correct water parameters for every kind of fish. You can add a water conditioner or re-mineralising buffer to achieve the desired hardness and pH for your saltwater or freshwater aquarium. In fact, many stores supply pre-mixed seawater that can be added straight to your aquarium complete with all the necessary minerals added.

Easy to Install

AquaFX Barracuda Aquarium Filter

Most reverse osmosis units are pre-assembled and easy to install. Budget reverse osmosis filtration systems require little effort to set-up and can be used almost immediately for your aquariums. For example, the AquaFX Barracuda RO/DI Unit has a quick set-up time and comes with very clear setup instructions. Also, your reverse osmosis unit can be tapped into existing plumbing through the optional saddles and tubing included in the unit.

Most users do not require professional help in installing a reverse osmosis system. You will only need to connect the supply line, drain line and product water line. You just need to find a location that has a source for cold water and a drain. You can then connect the filter to the source water and run the waste water line to the drain.

Water Efficiency

Many reverse osmosis systems come with an automatic shut-off valve which means that when output is closed, the input will also be turned off. The diaphragm valves work in conjunction with a pre-pressurized tank to automatically turn the reverse osmosis system off when the tank is full, then turns back on when the tank level drops below a certain pre-set point.

You can also purchase a zero-waste reverse osmosis system. This means that for every gallon of purified water produced, there is zero waste water generated. Users who prefer a water efficient aquarium will enjoy a zero-waste reverse osmosis system.


A reverse osmosis system offers a simple solution for making any tap water source safe for your aquarium. By using Reverse Osmosis (RO) purified water, you can avoid pollutants in your tap water entering your aquariums. These pollutants can cause nuisance algae and long-term problems for the development of your fish.

Additionally, by using purified water, the limitations of your local water can be removed. Through re-mineralisation, you can add crucial minerals to your reverse osmosis water to aid the growth and survival of your fish. With reverse osmosis water, you can also establish stable water parameters to recreate any aquatic habitat within your homes.


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