Fluval Foam Filter Blocks are designed for use with Fluval FX Series Filter models, including the FX4, FX5, and FX6. The custom fit blocks feature a snug fit to prevent bypass for more complete filtration. The foam filters have a pore size that allows efficient water flow with less clogging for improved performance and a longer life. The foam inserts also enhance biological filtration by providing an ideal medium for the growth of beneficial bacteria, which is essential for long-term tank health.

Fluval Foam Inserts are primarily used in the mechanical filtration stage to capture large particles and debris. Mechanical filtration is the first step in the filtration process. Fluval Foam Filter Blocks are suitable for use in freshwater or saltwater aquariums. Filters are sold in convenient and affordable 3 packs and shipping is always fast. Filters come with installation instructions. The simple foam block filters slide easily into place in the Fluval FX4, FX5, or FX6 filter without the use of any special tools or equipment.