Hozelock/Cyprio World Famous Green Machines conventional biological pond filters for fish ponds

Pond Filter Clean Water To Allow Fish To Survive in Their Own Pollution

The simplest of all pond filters is the “black box” type. The Hozelock Green Machines handles ponds up to 27,000 litres in volume (and that's a big garden fish pond). 

The Green Machine uses open cell foam and brushes used to mainly remove leaves, and larger particles of whatever can get into the pond filter. It has a limited amount of biological capacity

Plastic biomedia on which bacteria accumulate is used in the Green Machine by Hozelock/Cyprio

WARNING bio filters do not clear green or murky ponds as many people claim. To ensure a clear pond an UVC is needed ... this kills suspended algae which can then be removed by the bio filter. While still living algae are very very very tiny and just pass straight the pond filter. In other words for a crystal clear garden fish pond you need BOTH a bio filter and an UVC or ultra violet clarifier

The simplest homemade pond filters contain almost anything you can imagine from hair curlers to gravel.

BUT ... if it was me and because I'm a bit ham-fisted I would buy a box filter or a Hozelock/Cyprio Green Machine for larger ponds like this one above and shown in table below ... Hozelock produce a wide range of pond pumps to satisfy any size pond

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