A garden pond is a living breathing environment that has a continuous flow of waste products being transferred into the water by both its occupants and external factors. As the pond is a self contained environment, there are two possible outcomes. The waste products are either utilised by an organism within the pond or, somehow, somewhere the waste will build up.

Most of the waste products in a pond will be effectively utilised by another pond resident. It is this balance that enables a natural pond to survive without mechanical or chemical intervention. The one waste product that nature struggles to overcome is the build up of silt or sludge. Silt and sludge build up is the eventual outcome of a build up of organic waste. The organic waste is a mix of fish waste, plant decomposition, uneaten food and all topped off with those nuisance tree leaves that weren’t cleared out of the water.
Every pond will experience both sludge and silt build up over a long period of time. In nature, a key defence against this problem is simply the volume of water. Larger ponds will experience silting up over a significantly extended period of time. Even these ponds, without intervention, will eventually silt up. Smaller natural ponds are quite often only temporary in their nature and these will silt up far quicker.

A garden pond is at far more risk of silting up if left unchecked. The sheer volume of aquatic life present in a proportionately small body of water presents particular issues for excessive organic waste production. There are pond treatments available that will introduce bacteria to breakdown pond sludge and significantly reduce this issue. Ultimately, in order to remove silt build up you will need to clean out the pond. This is usually done through the use of a pond vacuum. The old fashioned technique of draining a pond and scraping all of the mess into a bucket or wheelbarrow is still effective but certainly less favoured.