The media inside your filter is completely down to personal preference. All our internal and external filters are supplied with various types of filtration. It's important to understand how filtration actually works before changing what is already supplied within your filter to ensure you are getting the maximum desired water quality. There are three different types filtration and each processes a different type of waste.

• Mechanical filtration – this removes solid waste, which is any particle or debris, such as uneaten fish food or bits of fish waste. It works by circulating the water through a foam-like material that traps debris.  Mechanical filtration keeps the tank clean and the water aerated.

• Chemical filtration – this removes dissolved waste, which is made up of organic compounds, such as decaying tissue, and the chemicals left in tap water, such as chlorine. It works by flowing water through carbon or resin that catches the dissolved waste. Chemical filtration prevents discolouration and keeps tanks odour-free and fish-friendly.  

• Biological filtration – this removes biological waste, specifically the ammonia that fish waste produces. It works by cultivating nitrifying bacteria to convert toxic ammonia into a harmless nitrate. This nitrate can then be removed through chemical filtration, algae absorption or water changes. This is the single most important type of filtration, as without it, the ammonia will rise to dangerous levels.

For more information about types of filtration, see this previously written blog.