(Mainland UK only)
Dust from the atmosphere and falling leaves will need to be cleared from the pond surface. Protein scum, caused by the use of airstones or a waterfall is another surface contaminant that has to be removed. In a koi pond, there should be at least one flush-fitting surface skimmer to remove the scum and floating leaves before they become waterlogged and sink to the bottom of your pond. In order to remove the smaller debris from the pond it may be necessary to use an external filter
