How to Use Reverse Osmosis Water in an Aquarium

Updated July 20, 2017

When keeping fish in an aquarium, you must keep their water clean and free from toxins, bacteria and harmful minerals. In most areas, the water available from the faucet is treated with chemicals such as fluoride and chlorine to remove impurities. These chemicals are harmful to fish, especially exotic fish. Using a water filtration system such as a reverse osmosis filter will ensure your aquarium remains a healthy and toxin-free environment for keeping fish. Reverse osmosis filters work by passing water through a membrane. This membrane removes almost all harmful toxins from your aquarium.

Place your aquarium within reach of a power source. The filter will run from the main power supply.

Attach a tank-mountable reverse osmosis filter to the back of the aquarium. The filter has a built-in clip that fits onto the lip of your aquarium.

Put the attached tube over the lip of the aquarium and into the water.

Plug the filter into your main power supply and turn on the filter.


Reverse osmosis filters are available from aquarium stores. You can buy water pretreated using reverse osmosis from aquarium stores and stores specialising in exotic fish.


Take care when using electrical appliances near water. You need to maintain reverse osmosis filters regularly to keep the membrane in good working order.

Things You'll Need

  • Tank-mountable reverse osmosis filter
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About the Author

Luke Boston has been a freelance writer since 2009, mostly ghostwriting for nutrition websites and ebooks. His articles specialize in health and nutrition. He is a qualified nutritionist with a Bachelor of Science in nutrition. Boston also received a Master of Arts in creative media practice.