How to Clean My Aquarium Filter (& Is It Necessary?)

Whether or not you have to clean your aquarium filter is a question that I get quite often, and it’s a legitimate question that deserves it’s own article.

The filter, as you already know is one of the most important pieces of equipment in an aquarium. It filters the water (obviously), it helps to oxygenate the tank and it serves as a hub for beneficial bacteria to thrive.

The problem is, mechanical filtration (the removal of dirt and debris from the water) is a big part of a filter‘s job, so it’s obviously going to “fill up” after a while and need cleaning.

But is it safe to do so? Let’s find out…

Before we begin, you may need some of the following tools to clean your filter:

• The API Stress Coat Water Conditioner: water conditioners remove the dangerous chemicals from tap water so you don’t harm your fish
• Aquarium Filter Pad replacements: if your filter media uses a filter pad, you’ll need a replacement
• Under-Gravel Filter: if you don’t want to deal with cleaning your filter as much

Yes, it is completely safe to clean your aquarium filter if you do it the correct way. Filters are hubs for the beneficial bacteria that keep your aquarium healthy, so cleaning them the wrong way can remove this bacteria and do more harm than good.

A lot of beginners will simply remove the dirty aquarium filter from the aquarium and run the media under warm tap water to remove all of the clogged up dirt and debris.

This is incredibly dangerous for the health of your aquarium for 2 reasons:

1. Tap water needs to be treated with a water conditioner to remove chlorine and other harmful chemicals before it ever comes in contact with any of your fish or equipment.
2. The beneficial bacteria inside your filter media has taken a long time to establish. Washing all of that away can completely collapse the entire ecosystem.

Biological filtration (one stage of aquarium filtration) is the process in which beneficial bacteria breakdown harmful chemicals and toxins into substances that are less harmful to your fish.

For example, ammonia (dangerous) is broken down into Nitrate (also dangerous) and then into Nitrites (safe in small quantities).

This process is known as “cycling” and it’s an integral part of keeping a healthy aquarium. It’s knowledge that every fishkeeper should be equipped with.

Now that you know how NOT to clean your filter, let’s break down exactly how you should.

The first step is to unplug the filter and remove it from the tank. It’s a good idea to move the filter straight into a bucket, as they typically spill excess water all over the place.

Fill another bucket or container with room temperature, conditioned water (you can use some of your aquarium water) and begin disassembling your filter.

Use the room temperature water to clean the filter media, removing most of the unwanted matter or until the water runs almost clear. You don’t want the water to be crystal clear since you want to leave some of the bacteria behind.

To clean the motor, the plastic cover and any other non-media parts of the filter, you can use warm conditioned water to give it a good clean. (Never use hot water to clean the filter media).

Once everything is nice and clean, simply reassemble the filter, place it back in the tank and turn it back on. If your filter media uses an aquarium pad, be sure to replace it during each clean. Job done!

Can You Clean and Reuse Fish Tank Filters?

Yes, fish tank filters can be cleaned and reused, but the method depends on the type of filter media:

1. Mechanical media (sponges, pads): Gently rinse in removed tank water during water changes. This preserves beneficial bacteria while removing debris.
2. Biological media (ceramic rings, bio-balls): Like mechanical media, rinse in tank water. Avoid using tap water, as chlorine can kill beneficial bacteria.
3. Chemical media (activated carbon, resins): Generally, these can’t be reused effectively. Once exhausted, they need replacement.

Regularly cleaning a fish tank filter ensures filter effectiveness. However, avoid over-cleaning, especially the biological media, to maintain a stable bacterial colony.

It depends on the size of your aquarium and the fish you keep. Aquariums with larger fish or a large quantity of fish will need cleaning more often, whereas large aquariums with a few tidy fish like tetras will need cleaning less often. With that being said, once every 3-4 weeks is ideal.

This advice is primarily for internal and external filters because they are the most common. If you are looking for a filter that requires less cleaning, an under gravel filter would be perfect.

The problem is, if you keep lots of plants, the under gravel filters won’t work as effectively as they need to, leading to complications with the quality of your water.

You can also try self-cleaning tanks, which we’ve created a list of the top 5 for you to choose from.