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How Often Should You Clean Your Aquarium Filter

A healthy (meaning biologically active) and clean Aquarium filter (meaning not clogged up) will determine whether your tanks inhabitants are living a healthy vibrant life or struggling every day to stay alive. Think of it this way the next time you think you will put off maintaining your tanks filter.

A fish in water is equal to a human breathing air. If our air slowly got toxic to the point that we started to die then that would just be terrible wouldn’t it? Well if you don’t keep on top of cleaning and maintaining your aquarium filter that’s basically what is happening to your fish.

Every day they are finding it harder and harder to function and eventually could die. The filter affects the water and the water affects your fish.

Determining how and when you should clean your filter will not always be cut and dry however you can clean it on a regular basis to create a healthy environment in your tank. I use primarily mechanical filtration and clean the sponge part of the filter every 3 to 4 weeks.

The routine you set up will be determined by a couple of things with the first one obviously being your schedule. The 2nd and even more important factor determining how often you clean your filtration will be the bio-load of the tank. The bio-load is the effect of all of the inhabitants combined from the aquarium with how big the aquarium is and what size of filter you are using.

What are the indicators of when your tanks filter needs cleaning?

  • The water starts to get cloudy with more and more small particulates floating around. If it has been a few hours since you fed the fish and the fish are not overly active and you are finding that the water appears cloudy or there are quite a bit of small particles floating around then you should probably have a look at your filter.
  • If you do a visual check on your filter and you see a good amount of sludge then it’s probably time to give the filter a cleaning. Even though some sludge is okay as there will be good bacteria embedded in it as with anything else in life too much is never a good thing.
  • If the water flowing out of the filter starts to slow down then that means your filtration system is clogging up.
  • If your fish start acting sluggish or just seem to be a bit off than normal I would treat this with a sense of urgency because the moment you can visually see the fish are stressed in any such way means there is an issue in the water. Check the filter and if the filter is fine then check the water parameters.

It’s okay to let your filter get dirty for a while before cleaning

It is alright to let your filter get dirty for a while. You actually want it to get dirty because you want all of the beneficial bacteria to grow which in turn keeps your tank water healthy. I know some people see a bit of sludge and feel it’s time to clean the filter before it gets worse and causes problems in the water but that’s just not going to happen.

You would have to leave the filter in a healthy aquarium for a couple of months without cleaning before it ever started to start an issue for the water and fish. It could even take longer if the tank started out healthy.

How to clean an aquarium filters sponge or filter Pad for mechanical filter

If you have a mechanical filter that includes a sponge and activated charcoal here is the quick and dirty way to clean your filter sponge. Just a quick note on the activated carbon/charcoal in your filter. You should change the charcoal bag out every 4 to 6 weeks.

You can also go off of what the packing of the product recommends however keep in mind that the company selling you the activated charcoal wants you to purchase as much as possible.

To clean a filters sponge it is important that you only use water from the aquarium to “rinse” out the sponge enough so it flushes away most of the guck in the sponge.

Dip the sponge into a container of your aquariums water and squeeze out the filter until you are satisfied that it is rinse out enough to put back in the filter.

It is important not to use any water other than the tanks water because doing so will kill any beneficial bacteria you have in the filter. Doing this could also trigger your aquarium to start the Nitrogen cycle again if you completely sterilize the filtration system.

If the Nitrogen cycle starts while there are fish in the tank that could potentially kill your pets.

Some aquarium filters have pads instead of sponges. These HOB and other mechanical filters are somewhat more streamline than their sponge style counterparts. If you have a pad instead of sponge you can do the same as above and rinse out the pad in the tanks water.

You probably won’t be able to squeeze the pad or it might bend or break. Just swoosh it around in the water to clean it up a bit.

I find that pads need to be changed more often than a sponge. I prefer filters with sponges in them. If you are in the market for a filter I always recommend HOB mechanical filters for beginner and experiences aquarium hobbyists.

Check this aquarium HOB filter out on Amazon or alternatively you could go check out my filter recommendation page which also helps out with matching up size of tanks to filters and different styles of filters.

How to clean an internal aquarium filter

If you own an internal aquarium filter you will have to unplug your filter and take it out of the aquarium opening it in a sink and rinsing out with the tanks water as described above for the mechanical filter sponges.

Once clean put your filter back in the tank then plug it in.

How to clean a carbon filter in your fish tank

As described above in the sponge cleaning section clean your filtration pieces in aquarium water.

However when it comes to activated carbon or charcoal you typically don’t rinse out the sack of carbon. The product is usually thrown out and a new insert installed. It doesn’t mean you can’t rinse and use the same charcoal. Just be aware though that activated carbon only stays activated for so long then loses its ability to absorb toxins in your tank.

When replacing the charcoal insert rinse the new bag of charcoal in aquarium water not tap water as you don’t want to rinse with chlorinated water and then add the chlorine to your tank.

Rinse the carbon and when it appears that less black coloring is coming from it go ahead and insert the new charcoal bag into your tanks filter.

How to clean an aquarium filters tubes

While you are cleaning your filters sponge you might as well perform some more maintenance and clean the inlet tube of the filter and any other tubing that is easily disconnected. These pieces can be cleaned with paper towel or a clean rag and having some pipe cleaners are extremely helpful for these filter parts.

Make sure to use aquarium water when cleaning the filter tubes as well.

An alternative water source for cleaning your aquarium filter

If you are running a sick tank (hospital tank or quarantine tank) feel free to use the water from this aquarium if you don’t want to pull water from the active tank. If you did a water change recently you might not want to take more water out to clean filter parts. However that being said you could sync up the timing of

Aquarium filter cleaning in a nutshell

There you have it in a nutshell. When cleaning your filter media make sure to use tank water and don’t clean the sponge or pad too often. Wait until there is a bit of a build-up of sludge or the water flow is decreasing.

Once you understand this you will see just how easy it is to maintain a tanks filtration system.

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