There was a time when many people did not even consider pumps and filters for their garden ponds and pools. But today, pond pumps and filters are amongst the most popular fish pond supplies available.
Still water in garden ponds is certainly beautiful, especially when the pond is planned to reflect plants and garden features. But moving water adds excitement and sound to the garden environment, an element that appeals to many people.
To make streams run and fountains spray, you are going to need some sort of a pump. You will also need a pump to run a filter. The basic choice is between pumps that work inside the pond, under the water, and those that are housed above ground, somewhere near to the pond. The most important factor to consider is size, and the volume of water that the pump can deal with. If you are going to use a pump to power a fountain, then you are going to need to know what water head it produces. This is the height to which the pump is able to make the water spray. Large water features and fountains clearly need a pump with a more powerful capacity, because of the volume of water that has to be moved. Waterfalls also need reasonably powerful pumps, to drive the water up to the top of the fall.
There are many different makes (or brands) of pump and they are manufactured with different types of housings. Generally the more expensive the pump is, the longer it is likely to last. For example, a plastic pump will cost a lot less than one that has housing made from stainless steel, but the cost variation is likely to be quite substantial. Make sure you choose a model that meets your needs, and buy the best quality you can afford.
There are various types of pond filters, all designed to keep pond water clear and to help prevent your pump from getting clogged with water-garden debris. Apart from leaves, twigs, and dirt that is inevitably blown into ponds, all kinds of decayed organic matter, algae, fish waste (excretion) and leftover fish food all need to be filtered out. While a pond with a well-balanced ecosystem will generally keep itself healthy and reasonably clean, it will never have crystal clear water – which is beneficial for ponds that are stocked with fish, particularly ornamental koi.
If you do have koi, or are planning to stock your pond with koi, then a biological filter is the best bet. Instead of just straining debris from the water, which is what a mechanical filter will do, a biological filter has a filter bed that contains live bacteria that actually breaks down toxic ammonia and other harmful substances that build up in the water. Bacteria converts the ammonia into nitrates, which plants need to grow.
Because it takes a few weeks for bacteria colonies to generate and grow large enough to be effective, once running, the filter should only be switched off for cleaning. Usually it is sufficient to rinse out a biological filter ever couple of months, and to replace filter media perhaps every year or so.
