Pump-fed, gravity-fed, trickle towers, centrifugal, sand, bead, multi-chamber, and pressurized filters all serve different pond filtration needs. Automatic mechanical and biological filter systems provide advanced self-cleaning and biological filtration, efficiently managing water volumes even without user intervention—ideal for garden ponds.

Each system has a specific flow rate and maximum pond size capacity. For expert guidance, consult That Pond Guy in the UK or explore top-quality filtration solutions from Burtons Aquatics.

If your filter system does not work properly as per your expectation then check whether you have committed any of the following mistakes.

1. The fish pond filter and the aquarium canister filter are not the same

Many hobbyists assume pond and aquarium filtration are the same, but they differ significantly. Aquariums, being smaller with lower fish density, can function well with one or two canister filters. In contrast, outdoor fish ponds face challenges like sunlight, temperature changes, and debris, requiring a powerful filtration system.

A pond needs physical and biological chambers with a proper filtration-to-pond ratio to maintain a healthy water environment for koi, ensuring continuous water quality and clarity.

2. Nitrifying bacteria have also got the functions of decomposing excrement.

The decomposition of pond excrement depends on heterotrophic bacteria rather than nitrifying bacteria which means implementing nitrifying bacteria exclusively does not provide lasting results. The decomposition process of fish food, along with waste, produces ammonia and nitrite that nitrifies bacteria and transforms them into harmless substances.

A stable filtration system depends on using filter media that is non-toxic in the bio chamber while enabling beneficial bacteria to spread across a sufficient area for biological filtration and improved water quality.

3. Water circulation can also play a filtering role.

Koi ponds are relatively closed aquatic environments. Water circulation merely promotes the flow of water to increase the amount of oxygen dissolved, but it cannot effectively filter dangerous compounds and germs in the water.

4. A koi pond requires only a physical system capable of filtering out fish faeces and other contaminants.

Some hobbyists believe that “clear water equals good water.” It is wrong. Many things influence the lives of koi in the fish pond. Aside from dung and other pollutants, there are germs and microorganisms.

The unseeable substance is more difficult to filter than the visible contaminants, and only a thorough filter system can achieve a higher filtration efficiency.

5. Cheap filter media performs the same as an expensive one.

There is a saying that you get what you pay for. It may not be applicable to other industries, but in the water filtration industry, greater quality always equals higher prices due to the use of better-grade raw materials or RoHs standards.

However, if you consider the product lifespan or the amount of care required, more expensive products may save you money. Take the Mountain Tree filtration brush, for example; it is large, but it comes with a three-year warranty.

When compared to conventional brushes, they need to be replaced every one or two years, therefore higher quality items will save you a lot of time to enjoy your fish – spend your valuable time doing what you love.