Update Your Site & Language

Type of Retailer

  • Premium Dealer Premium Dealer

    An officially recognized retailer offering a wide array of Fluval products and expertise.

  • Authorized Retailer Authorized Retailer

    An officially recognized retailer offering a selection of Fluval products.

  • International Distributor International Distributor

    The authorized distributor of Fluval products within a specified country or geographic region.

Items Added to Your Cart

0 Item in Cart

Shipping & Taxes calculated at checkout

View cartCheckout

Filtration & Media


November 2, 2021 | By Tom Sarac

There are many choices when it comes to biological filter media, which begs the question: what should you look for when choosing a quality product? To answer that question, let us consider the following important topics.

Brand and Engineering

Like many other purchase decisions, our first suggestion is to look for a recognized, respected brand name. Try to find one that is known for producing high-quality biological filter media, and most importantly, manufactures power filters. The engineers that design aquarium power filters consider many important filtration-related parameters while they do so, making them most likely to also design the best performing filter media.


Biological filtration performance is significantly influenced by the type and characteristics of the media you select. Choosing a filter media that offers a wide variety of inter-linked pore sizes, from its surface to its core, is best. Why? Different species of nitrifying bacteria have different requirements and tolerances in terms of water flow, oxygen levels, and light exposure. Furthermore, there is the additional benefit of prolonging contact time to improve biological filtration.

The porous nature of filter media such as Fluval BIO-FX offers a vast surface area for the colonization of nitrifying bacteria. In fact, BIO-FX provides a massive 2,250 square meters of surface area per liter of media, allowing for excellent biological filtration performance in even the most crowded and heavily stocked aquariums.


The shape of filter media and the resulting void space is also a factor. The shape should allow for adequate water flow through the media to avoid debris blockages, which can result in channeling of water flow and a reduction of filtration efficiency. Cylindrical-shaped bio-media allow for excellent water flow around and through each cylinder, preventing debris and waste from accumulating and clogging water flow. In turn, this supports oxygen levels and ensures subsequent filter media receive an evenly distributed water flow, improving filtration efficiency.

Water Chemistry

Last, but certainly not least, choose filter media that is inert and does not alter water chemistry. Filter media should not leach and/or impart compounds that can substantially harden water or change its pH. This will aid in providing stable water chemistry and will allow the media to be used in both soft and hard water aquarium environments, which is important for the long-term health of aquarium inhabitants.

Like all other filter media, regular maintenance is important for the best long-term performance. However, there’s one important difference: when it comes to biological filter media, it is strongly recommended to only rinse it with aquarium water to minimize the loss of nitrifying bacteria. Good filter maintenance practices will guarantee that your aquarium filter offers the best environment for nitrifying bacteria.

As mentioned above, the engineers that design power filters are the best at developing the optimal filter media for them. Fluval BIO-FX is a premium biological media designed for use with canister filters and sumps of all sizes, including the flagship FX series and 07 series. Featuring a deep pore structure with interconnected micro-tunnels, BIO-FX offers a vast surface area where billions of beneficial nitrifying bacteria can thrive. Whether you own a Fluval filter or not, consider Fluval BIO-FX, the #1 choice of the engineers responsible for the development of the world’s best-selling line of canister filters.

Learn more about BIO-FX: https://fluvalaquatics.com/us/product/bio-fx-5-l/


Videos & Articles

Based on your browser settings, we've redirected you to the United States English Fluval website.

Update Your Site & Language