Filter Maintenance

The filter is essentially the lifeline of your aquarium and looking after it will go a long way in ensuring your fish’s long term happiness and health. It houses bacteria that break down the natural waste produced by the bio load in the tank, it pumps water thus creating circulation within the aquarium to avoid stagnant water, it creates oxygen exchange into the aquarium depending on where the filter outlet is faced. These are the basic positives of most readily available filters. Now the more advanced and the bigger your filter is it can house multiple varieties of filter media such as sponges, carbon and ceramics each providing a benefit of their own. Smaller filters may only house a sponge as media.

Some people argue the necessity of the additional media such as carbon. Carbon while not essential it has it’s uses such as removing medication from your tank after a course of treatment, absorbing some of the harmful components of water to your fish such as chlorine, chloramine and some metals found in the water column. This type of activated media which also includes Ammonia Remover and Clearmax Phosphate Remover (commonly found in Fluval filters) loses it’s effectiveness after a period of time and will need to be replaced in order to continue working. Note: even after loosing effectiveness these media will still house the useful bacteria needed to maintain a successful aquariums. Most manufacturers recommend replacing this type of media after 1month of use.

Sponges are also a common occurrence in filters in fact all filters will have some sort of sponge media which is used to house useful bacteria and filter larger particles of waste flowing through the water column. These sponges will also need replacing as part of maintaining a healthy aquarium but will generally last much longer than other types of media. Most manufacturers recommend replacing sponges after a period of 6months as a guide but they will need to be cleaned throughout that time.


Please note the below maintenance times are only guides and are in assumption that you are carrying regular partial water changes.

It may feel like hard work replacing and cleaning filter media but it is essential in keeping you aquarium running. Depending on your bio load and how many filters you are running your maintenance schedule can differ, for example in a heavily stocked aquarium running only 1 filter suitable for the aquarium size maintenance should be done more regularly (at least once a month), on the contrary an aquarium with low bio load and 2 filters suitable for the aquarium size maintenance can be carried out more sparsely (once every 2months or so). Getting a bigger filter or adding a filter does not necessary mean you can increase your bio load as there are other factors to consider such as size of fish and size of aquarium but I would recommend if you have the space to always go with 2 filters each capable of running the should one fail. This also helps with maintaining your filters as you will always have a filter fully functioning while the media in the other is being replaced.

It is ESSENTIAL not to change all the media at once as this may cause a mini-cycle in your filter because too many of your useful bacteria have been removed at the same time.

How to clean filter media:

Never use tap water to clean your filter media, this is because the same chemicals harmful to your fish found in the water are also harmful to your bacteria, also the temperature different from the tank water to your tap water can kill a significant number of the bacteria if not all. The best way to clean your filter media is to schedule it with one of your regular water changes.

  • Turn off your filter and all other electrical equipment such as the heater before putting your hands inside the aquarium.
  • Take out some tank water into a bucket.
  • For INTERNAL filters: just disassemble the components and put all the media into the bucket of water. Rinse the trays in the bucket water and squeeze the sponges in the bucket to give them a good clean. Don’t over clean as again this can cause too many bacteria to be removed from your media.
  • for EXTERNAL filters: make sure the stop valve is closed to avoid water spilling out. Open the canister and drain all the water out in the sink. Remove the media and place them into a bucket of aquarium water and squeeze till they are visibly cleaner. This is a good time to replace any media past it’s usefulness. Reassemble the filter and connect it back up. If your intake pipe is still submerged you can now open the valve to let the canister fill up again, then complete your water change and turn on everything. If your intake pipe is no longer submerged then fill up the aquarium first before allowing the canister to fill.