Guide to Garden Pond Filters
Which Pond Filter Should I Buy?
There are several different types of garden pond filter on the market, varying widely in price and individual suitability. They all however, are designed to be the ideal residence and breeding ground of billions of bacteria, good bacteria! All these bacterial colonies need is a plentiful supply of Fish waste and oxygen.
They are known as Aerobic bacteria and colonize every available surface. This is why all pond filters are designed to provide maximum internal surface area. They all provide varying degrees of biological and mechanical capability. Here is an overview of the different types you may come across.
Gravity Return Filtration
This is a very simple filtration technique where the pondwater enters and passes through a mechanical agent such as foam or matting first to remove any solid debris. Next comes a high surface area biological media and exit back to pond via gravity. Can be cost effective but has the major downside that the filter exit must be above the highest level water return ie.waterfall. Can be placed next to the pond in a planted border or boxed in for seating etc to disguise it. Has generally been superseded by the pressurized option.
Ultra-violet filtration is used to kill algae spores, fungal spores, parasites and bacteria and is a very effective means of controlling green water and many fish diseases. They are rated in watts & come in many shapes and sizes. Many are now combined with bio/mechanical filtration, to offer an all in one filtration solution. The important thing to bear in mind with uv filters is the flowthrough rate of the water past the UV light source. Too fast and the nasty critters your trying to eliminate will not receive a good fatal dose. Do not give yourself a fatal dose either, this type of UV light is VERY VERY BAD for your eyes. Never look at a lit bulb. (This wont be a problem if used according to manufacturers guidelines)
This modern technique works on exactly the same bio/mechanical filtration principles. However, it does have a couple of cool advancements. Because there is little loss in pressure as the water moves through the filter, the outflow can be directed upward through flexible piping to the head of a watercourse or other high feature. The body of the filter can be buried and easily hidden. The most cool advancement is ‘backwashing’. At the push of a button the solid waste is exepelled from the filter, much less messy maintenance. Magic! Some models even come with a cleaning indicator.
If you are interested in building a large pond for koi carp you will need to invest in a high quality filtration system, these fish need and deserve sparkling clear water. This link will give you detailed information on various types of Koi pond filters and how to buy or make the one ideal for you.
