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Pond Filters:

pond filters

When keeping fish an effective filtration system is vital. Firstly and most importantly it keeps the water healthy, helping the fish to breath and thrive, and it also keeps the water clear so you can see them.

Size of filter required

This depends on the volume of water and how many fish you anticipate being in the pond. As a rule of thumb:

No fish - the volume of water should be filtered once every two hours.
Light fish stocks - the volume of water should be filtered every hour and a half
Koi - the water should be turned over every hour.

Bear in mind that each pond has it's own characteristics. For instance if a pond is in full sun the water needs to be turned over 25% more quickly. Similarly pond depth and water temperature also make a difference.

Choose from

Flow-through
The dirty water is pumped into the filter and then is returned to the pond under the force of gravity. The filter must be positioned higher than the point of return.
Flow-through with UVC
UVC stands for Ultra Violet Clarifier, a recent innovation that makes algae clump together so it can be caught by the filter, resulting in very clear pond water.
Pressurised
A more modern approach is to employ a pressurised filter that pushes out the dirty water under pressure. This means that there is greater flexibility in the positioning of the filter.