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Filtration - Box Filters

21st Nov 2019

Box filters are the best way to provide filtration to most garden ponds, they give longer contact time with the pond water delivered from your pump and the media within your filter. The reason why the there is a longer contact time is that the water is pumped through into a bigger filter unit in comparison to a pressurised filter, and also has a slower flow, this provides the water with more time to be cleaned. Here at Bradshaws we stock a wide range of box filters which come in a huge range of sizes that will cope with all but the biggest of goldfish ponds and smaller koi ponds. A ponds filtration is vital for any water gardener wanting to introduce fish to their pond, box filters help maintain a healthy nitrogen cycle through the promotion of friendly bacteria in the biological filter media, and the box filter will also stop the pond going green and cloudy with the help of a UVC and mechanical filtration.

Installing a Box Filter, Pump and UVC

Box filters all release water with the help of gravity, so they have to be situated above water level. Most people will choose to hide their filter with the aid of a waterfall and rockery combined, which is built around the filter itself using any shrubbery to make the filter look as natural as possible. Other people will choose to have the filter sat by the side of their pond due to space or maybe time restrictions, but again this can be hid by building a bamboo box around the filter and hiding with plants. If you're able to instal a box filter rather than a pressurised filter it is always better to do so as the filtration as a whole is better, so be imaginative and get thinking of clever ways to disguise your filter!Almost all box filters can be bought with a pump at a reduced kit price, so if you're upgrading your full system, these deals from us at Bradshaws are the best way to buy a box filter and filter pump together. To install your box filter and pump, the only other equipment you will need is a length of polyhose and the relevant hose clips to secure the joins which will prevent any leaking happening.Most modern box filters will now come combined with a UVC inbuilt, this has already been matched perfectly to the filter and if you buy it with a pump, not only does it save you money but this has also been matched together aswell for you. A UVC flocculate (clump together by damaging the outer layer of an algae cell) the algae, this makes the algae stick together into larger particles. These particles which would have been too small before to be filtered out by the mechanical media in your filter (foams) is now filtered out with ease, which stops your pond from going a murky pea soup green colour.

What does a box filter do and how does it filter your pond?

In a simplified explanation you will have a filter pump that sits within your pond, this will suck water and solid particles up to 10mm and then sends this through hosing to your box filter. The water then slowly works its way through the filter and is returned via gravity back to the pond clean.The way in which pond water is cleaned though, is what makes a box filter so efficient. The water from your pond in all box filters (except the Hozelock Ecocel) is first met by a UVC, it is here where the tiny algae cells that if left unattended would turn your pond to a green pea soup stagnant mess are dealt with. The UV bulb clumps together the tiny algae cells by damaging their outer layer, which in turn means that algae cells will merge together forming bigger particles. Next the rest of the solids that have travelled through the polyhose and the algae will drop into the main chamber of the filter. The water will now filter through foam layers in your box filter, most box filters will have 1 - 3 foam layers which will vary in density to make sure that all the solids have been removed. You may notice that most foam layers have a strange pyramid like design, this design not only helps to separate the layers from each other but it gives a huge increase on the surface area of the media, which basically means that you shouldn't depending on how dirty your pond is have to clean the filter foams as much!Once the water has passed through the foam layers it will be pushed through the biological filter media, there are many different types of biological media, the most common probably being flocor. These ribbed shaped circular plastic pipe shaped pieces are where all the friendly bacteria will cultivate within your filter, as all waste within the pond, be it from fish, food or plant life will create poisonous ammonia. Naturally occurring bacteria in your pond change the harmful ammonia into nitrite this though is still harmful to pond life and is where the friendly bacteria in the filter comes into play. The bacteria which is in your filter will turn nitrite into nitrate, this is a still slightly poisonous but it is also a plant food, so the more plants you have the healthier your pond will become when using a proper box filtration set up.