The Weald Aquatics Blog - Fitting a New Filter to an Aquarium - another blog post from Weald Aquatics | Aquarium & Pond Fish Shop in Kent


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Fitting a New Filter to an Aquarium

Blog post written by Gary | 24 June 2016 | Category: Aquarium equipment

If you are going to upgrade your existing internal or external aquarium filter, you will need to avoid losing all the beneficial bacteria in the filter.

To maintain good water quality when changing filters, you will need to run both the new filter and the old filter together for two weeks. This will ensure that the new filter will mature  with beneficial bacteria colonising the new filter media from the old filter. Adding Bacterlife which is a filter starter will also help to boost and maintain the bacteria in the new filter.

Having checked your water quality and made sure that the ammonia and nitrite levels in the aquarium are correct, the old filter can be removed.

Should your filter fail before a new filter has been installed in the aquarium, you can use the media from the old filter and place it in the new filter. If you are replacing the filter with the same make of filter this will not be a problem; however if the new filter is different then you may need to cut the old media to fit the new filter. By using the old media you are still retaining the beneficial bacteria which will help keep the aquarium water in good condition. Again adding Bacterlife to the aquarium water will boost the bacteria in the new filter.

Once the aquarium water quality is correct, then the old media in the new filter can be gradually replaced over a period of weeks.


Eheim filters. On the left is an Eheim external filter and on the right, an internal filter.