How Do I Do Water Changes In My Aquarium?

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Water changes are an essential part of routine aquarium maintenance and must be done regularly. The two main reasons for doing a water change is to reduce nitrates and replenish used minerals (hardness) which help maintain stable water chemistry.

The amount and frequency of water changes varies with each tank but as a rough guide, around 25-30% weekly or fortnightly is a good start.

When doing a water change, you should always start with cold tap-water, as water from the warm tap can contain copper and other heavy metals from your heating system. Hot water systems which are fed from a cold tank in the attic may also contain such things as dead creatures which can pollute the hot water. Boiling water from a kettle can be added to a bucket of cold water to warm it.

Tap water contains chlorine and chloramines, which are harmful to your fish and the bacteria in your filter, so you need to add a de-chlorinator to the water before it is used in the tank.

Once the new water is ready, you can siphon out the same amount of water from the aquarium. This is a good time to use a gravel cleaner, which also removes water, and also to clean the filter media, which can be done in the removed water.

Slowly top up with the new water and your water change is done. For more information on water changes, and to work out exactly how much you should be changing, read our article on Water changes in a Fish Tank

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