Silt is an unavoidable waste product found in each and every pond. Regardless of how clear your water may be or how well planted and maintained there will always be a gradual build up of silt occurring and collecting at the bottom of the pond.
Silt is quite simply the build up of waste organic matter that has broken down. Any organic matter that finds its way into the pond without being utilised in some form, will ultimately contribute to the silt build up. This organic matter is typically uneaten fish food, fallen tree leaves and dead plant matter.
There are some preventative steps that will significantly reduce the rate at which silt builds up. These revolve around having a little and often feeding regime for your fish, using netting over the pond in autumn to collect falling leaves and ensuring that the aquatic plants are kept well maintained to avoid dying leaves and branches finding their way to the depths of the pond to decay undisturbed. Removal of blanket weed is another good practice to follow. The use of UV clarifiers combined with a pond filter does remove one of these sources (algae) far more simply than was possible only recently. Whilst a filter is a great tool in the modern pond, it is of very limited use when tackling silt, other than when removing UV treated algae. A pond filter is primarily a tool for tackling chemical imbalance rather than physical waste products.
When it eventually comes to removing silt from the pond there are two options available, draining the pond and shovelling the stuff out which is a tried and tested method for the purist or arguably those with luddite tendencies. Alternatively there is the far more popular approach of a pond vacuum. As with all technologies there are an array of vacuums on the market. Dependent on the size of your pond and the current silt build up, some are more suited to a regular maintenance regime than an all out clean up job. Whatever the circumstances, choosing an appropriate model takes much of the unpleasantness out of the job.