Pond filter - Do you need one?
The pond in your garden may look very natural with its overflowing pots, its healthy and happy fish and crystal clear waters. But, as you know the pond there was not put in by Mother Nature, and we cannot rely on Nature to clean what we have put in. The liner at the bottom may not be showing and all the rich plant life around the garden may give you a sense of well-being. But, beware! The pond you have made has a bottom made of rubber, circulates the same water over and over again, and can never really be thoroughly cleaned out. Add to that the fact that you probably have a large number of fish in there!
Effective pond filtration is one of the must haves for a well-kept garden pond. If you want your pond water to be clean, clear and healthy pond filtration is the only way out. Natural, biological and mechanical filtration - all has to be used in combination to keep your pond water clean. If your pond is mostly decorative and houses nothing more than a very few frogs, then the pond filtration techniques you need to adopt are low-key. Trimming the vegetation, clearing any stray and dead leaves using a mechanical filter may be all that you need for such a pond. The goldfish pond also requires relatively low-maintenance pond filtration. Sufficient aeration, water and a small pond filtration system is all that you will need to keep this pond water clean. Koi-fish ponds, on the other hand, require intensive pond filtration systems. The water quality has to be excellent if the fish are to survive.
The usual thumb rule about pond filtration is that if your pond has fish in it, pond filtration systems are a must. Fish give off wastes and generate a lot of undesirable elements like Carbon Dioxide, Nitrates and Ammonia. Fish waste has to be cleared off before it gets dissolved and diluted in the water. Less nitrates also means less algae.
One effective technique used in pond filtration is biological filtration. Introduce a thriving colony of beneficial bacteria into your pond. If the number of fish were relatively small, this would be an effective system in itself. The bio-filter material should have lots of dissolved oxygen and good water flow. If the bio-filter is kept outside the pond, it is easier to clean. The bacteria also prefer air-moistened areas to grow in.
No pond filtration system is complete without a mechanical filtration system that removes all large waste materials from the water. Different kinds of mechanical filters perform this to varying degrees. A pump pre-filter traps the solid waste matter before it reaches the pump. This is a very useful kind of pond filtration. The pre-pump filter does have a small number of good bacteria, but this alone is not enough. Commercially available settlement tanks are very handy when the debris in the water is big enough to settle at the bottom. Direct waterflow through a filter material so that it traps waste is another form of mechanical filtration.
Pond filtration is not complete if there is algal bloom in the water. Both biological as well as mechanical filters are ineffective against algae. Biological filters do help to some extent, but this is not enough to keep the pond algae-free. An ultraviolet-modifier maybe used to keep algae down. The UV comes in various sizes. The principle behind UV clarification is that once water flows past the UV bulb in the filter, all single-celled organisms will die. But UV lights are ineffective against string algae or blue-green algae. Besides, UV lights will also destroy the beneficial bacteria growing in the pond.
A good bio-filter system combined with an effective mechanical filtration system is the best pond filtration system possible. When selecting filtration equipment, always think "BIG". UV clarification can be used if there are too many fish and any suspected growth of disease-causing bacteria.
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Koi Fish Pond - An introduction to Koi ponds and their maintanance
Pond fish - An introduction to suitable pond fish.
Pond fountain - An introduction to pond fountains
Pond plants - An introduction to pond plants
Pond waterfall - An introduction to pond waterfalls and how to build them.
Turtle pond - An introduction to Turtle Ponds
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