Koi Pond Pre-Filtration is extremely important in any pond. Solid waste are introduced on a continuous basis in any pond and can originate from a variety of sources. Algae growth, excess food, fish waste, leaves and other yard debris,and aquatic plant material all accumulate and foul your pond. A pre-filter or mechanical filter is focused on removing these solids.
The pre-filter such as a Cetus Seive will help to protect the circulating pump from clogging and prevent solids from entering the bio filter, overloading it and reducing it's effectiveness. They will also reduce maintenance, you won't have to clean that small pump basket every day or so!