How Often Do You Change Filter Floss – Easy Guide

Filter media is placed in your filtration stem. It will change the water quality as it flows through the filter. There are 3 types of filtration media; chemical, mechanical, and biological. Within those three categories are different media substances that you can use, such as; sponges, pads, bio balls, filter floss, and more.

Mix and match these to produce the optimum aquarium set up for happy and very healthy fish.

How often do you change your filter floss? It is recommended that you change out your filter floss every 5-7 days. Filter floss is a form of media that you use with mechanical media in your filtration system. A lot of the time-frame will depend on how big your tank is and how many fish you have in your tank. 

Filter floss takes care of built-up debris and microscopic bubbles that make your water cloudy. It is extremely easy to use and to change. 

I am going to provide you with all of the information that you need concerning filter media. Biological, chemical, and mechanical as mentioned in the first paragraph.

I will also give you the ins and outs of the products that you use with each type of media. With your filtration system being one of the most important components, I want you to have all the information that you need to make an informed purchase.

Main Types of Aquarium Filter Media

Filters keep the aquarium nitrogen cycle going and the fish in your tank healthy. The filter media changes the water quality of the water that flows through it. With so many types, you can customize your filtration system to achieve the optimum aquarium environment. 

The 3 Types Of Filter Media:

  • Mechanical
  • Biological
  • Chemical

All 3 of those filter media are suggested for all aquariums. You should use no less than mechanical and biological media. Most filtration systems sold today, come with all 3 media options.

The 3 types of filter media each use separate substances to achieve their function. Let’s take a closer look at the 3 main types.

Aquarium Mechanical Filter

This type of media will sit inside of your filter. It will physically trap and filter away the solid waste that goes through your filter. It removes the particles in your aquarium in 2 ways; surface and depth filtration.

Mechanical media helps with the efficiency of your biological media. This is part of the reason it is suggested that you use both mechanical and biological media because they work so well together. 

There is extra-fine, fine, coarse to medium, and very course mechanical media. The larger the pores are in your mechanical media, the larger the waste particles need to be for the filter to extract them. Course mechanical media is the most recommended. It is easier to clean and reuse than others.

Aquarium Biological Filter

This type of filter media is used to help the good bacteria grow. Good bacteria also grow on the rocks and other decorations that you have in your aquarium, which enhances the cleanliness and health of your tank. This is an essential part of your filtration system. But, it is recommended you purchase the best biological media that you can, to keep your aquarium in prime condition.

Biological media breaks down the harmful elements, such as ammonia. Converting them to less harmful nitrates. Easily explained; known as the nitrogen cycle, it moves harmful waste through your filter. 

Aquarium Chemical Filter

This type of media isn’t used as often as the other 2 types. That is why it was stated earlier that at a minimum you need to have mechanical and biological media. Chemical media is available in a large variety of materials. Depending on the material it can remove many impurities or just one.

Chemical media helps your aquarium maintain water quality and removes dissolved particles from the aquarium. The two chemical media substances most used are active carbon and resins. We will talk more about those later in this article. Chemical filtration maintains water quality because the unwanted, dissolved matter will stick to it.

Out of the 3 types of filter media, the biological is the most important. If you do not have effective biological filtration, it could kill your fish. Remember; mechanical and biological are highly recommended, minimum. All 3 types of media are suggested. 

Aquarium Mechanical Filtration

A deeper look at mechanical filtration (media) will give us a better understanding of how it helps your aquarium. It is the easiest type of media to use. Even though it is the simplest, it is still very important to the overall health of your tank.

Mechanical filtration is the first stage and needs to be placed so that the water hits this media first. Mechanical media promotes the growth of beneficial bacteria.

Types Of Mechanical Filtration Media 

Some media options are sponges, pads, filter floss, bio-balls, and others. The type of filter you have will make some of the media substances semi-dependent on them. In some cases, your mechanical media will also hold your chemical media substance.

An example is cartridge media which is used in some power filters. Some of the filters on the market will have many layers of mechanical media. 

Pads Media
These are used in canister filters and some power filters. The same goes for sponges and foam blocks. Depending on the shape of your filter basket, you can buy them in circles, squares, or rectangles.

Choose the pore size that matches the purpose of the pad. If you are using it as the “first-stage” you want to choose course pads. They will trap the large particles.

If you are using it to finish the water, as it exits the filtration system, then you want to purchase a very-fine pad.
Filter Floss
Used in the canister, wet/dry sump, or even trickle filters, filter floss originated when most aquariums were equipped with tank box filters. You just stuffed it into the box. Some aquarists, who do not care for carbon media, will remove the carbon and replace it with filter floss.

Filter floss is the most efficient way to attain crystal clear water. You want to change your filter floss every 5-7 days to prevent the accumulation of decomposing debris. You may have to do it more often depending on the number of fish in the aquarium.

Some other advantages of filter floss; it does most of the filtration, substantially reduces build-ups, you don’t have to wash other filter media as often, and it is easy and quick to change.
Biological Media
This type of filter media mimics what happens in nature. It breaks down the toxins in the tank; nitrate, ammonia, and nitrite. It also provides the environment with a place for healthy bacteria. The biological media work with the mechanical (and chemical) media to clean your tank water and rid it of harmful elements.

There Are 3 Main Types Of Biological Media Substances

  • Rocks; lava rocks provide an excellent place for beneficial bacteria
  • Balls; normally plastic, are made to create turmoil. This allows the perfect mix of air and water to create good conditions for the bacteria to thrive.
  • Ceramic Cell-Pore; these are cut to fit the opening in the filter and are extremely porous. An exceptional way to provide biological filtration.
  • Glass balls; are very common as a biological filter.

The advantages of biological media, which is highly recommended, are as follows; clear water, a healthy environment, keep levels of harmful substances away and get rid of ammonia and nitrates.

Aquarium Chemical Filtration

Chemical filtration will remove ammonia, nitrates, and nitrites better than the biological media. This is why mechanical, biological, and chemical filtration media are suggested. They all work together to keep your tank in prime condition for your fish. What mechanical and biological can not get rid of, chemical media will.

Chemical media will remove heavy metals (copper), sodium chloride (salt), tannins (from driftwood), ammonia, and nitrates.

Aquarium Activated Carbon 

The most popular and most used chemical media. This is affordable, easily available, and can remove a large variety of things from your tank water. Along with the list above, it can remove; chlorine, dissolved proteins, nasty smells, and discoloration in the water. 

You can also use resin, oxide, and zeolite. Make sure you read all instructions and suggestions on filter media substances, from the manufacturer. 


Filters are essential in keeping your tank healthy. Without a filter, you would have dirty water full of chemicals and dead fish.

3 types of filter media, substances and replacement schedule:

  • Chemical- activated carbon – replace every 3-4 weeks. Once the carbon gets clogged, it no longer works and can actually start putting the bad chemicals back into the water
  • Mechanical – filter floss – change every 5-7 days maximum depending on tank size and how many fish are in the tank.
  • Biological – bio balls – these are not the best, but they do work and you never need to replace them. 

Remember, there are other substances besides the ones above, in each category. Research and find which substances are going to be the best for your tank and your fish. Most filtration systems now come with all 3 types of filter media.

But you want to at least use the mechanical and the biological, to keep your tank healthy for your fish. All 3 are your best option. You can mix and match the substances that you use to make your aquarium the best environment for your fish. 

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I'm passionate about fish pets and love sharing everything I learn about them.

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