How to Change the Water in a Fish Aquarium

Check the Water to Decide If It Needs Changed

Look to see if the water is cloudy.

Use a water test kit to see if the water is the correct pH level. If not, it needs to be changed.

Remove Part of the Water From the Tank

Use an algae scraper to remove any algae from the sides of the tank before you change out the water.

If the filter is dirty, clean out part of the components at a time. If you clean it all at once, you will lose parts of the healthy bacteria.

Siphon out 10 to 25 percent of the water. Use the siphon around your gravel to remove the waste and other matter.

Put in the Clean Water

Fill a bucket with tap water that is the same temperature as what is in the tank. Use a bucket that is only for the aquarium so that you don’t get other chemicals and contaminants in the water. If the tap water is not the right temperature, you can leave it out for a few hours at room temperature.

Add any necessary additives, like salt for a saltwater tank, or nitrates/potassium. Always add a water conditioner (with Stress Zyme if you need some slime coat protection) to get rid of the chloramines/chlorine. Not doing so will result in damage to fish gills and a slow death!

Check the pH balance of the water. If you are using straight tap water, you will need to put some neutralizer in it and let it set for a minute. Test it again before putting it into the tank.

Use the siphon to put the water back into the tank. This is better than pouring it in because it won’t upset the fish or the decorations.

Test the water again after an hour to make sure it has the right chemical balance.

Finished.