How to Select a Fish Pond Filter

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Why You Need a Pond Filter and What it Does

It's important to realize that a pond filter is first and foremost required to purify the pond water ... fish pollute the water as part of their natural metabolism and if the impurities are not removed toxic levels of pollutants are reached. In such circumstances fish would become stressed and might even die. A filter is also useful to remove suspended solids from the water.

If your pond is small to medium and you do not intend to stock with expensive fish then there is little need to overspend on a filter with all the bells and whistles and hype. Most modern filters from the likes of FishMate, Hozelock, Heissner, Blagdon and Oase will do an excellent job. Price is not the determinant of how good the filter is. Your choice will be between a gravity (box type) filter and a pressurized one. See list of all USA pond filters below.

Three kinds of pond filters

Gravity filter Low cost gravity flow pond filters used mainly in small to medium ponds. The picture is of of a FishMate gravity filter which is sold worldwide and is an excellent low cost system because it incorporates high efficiency biomedia. In simple terms it is the type of biomedia that determines the physical size of the filter box and this has a bearing on how easy the unit can be hidden in a landscaped garden.

Pressurized filters can be easily hidden and in many cases can be cleaned with little hassle. These filters (picture shows an example from the FishMate range but all models have a similar shape) have started to dominate the market. The reason is that these filters are efficient and small in size compared to a box type gravity filter. One of the biggest advantages however is that they can be remotely located or even buried to allow for more natural appearances. The units require a higher pressure pump than with a gravity type filter and very often the unit is sold with a suggested pump. However so long as you follow the recommendations in the pump selection page you will be fine.

Aquabead filter no UV Specialised pressure or gravity filters designed specifically for large ponds. For this type of filter the same principles apply but other considerations need to be applied also. Read the sections on advanced filtration because this choice is critical to pond success. The Aquabead or Aquadyne filter in the USA is good and in the UK the tendency is towards Vortex type filter installations.

The principles behind correct specification are the same in all filter types.

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You Must Know Your Pond Volume ... That's All

To specify an appropriate pond filter it is important to know the volume of water in a pond to about 80% accuracy. A filter is specified in terms of what capacity it can handle when the pond is stocked normally which needs some interpretation. In general the more fish in a pond the greater the level of pollutants so a larger filter would be used.

How to select a pond filter (also called biofilter)

A filter will claim to handle or purify up to 5,000 litres of pond water. The claim will be based upon qualifications such as fish stock density, amount of food fed and so on. If you can afford it always go slightly bigger to get better performance.

A pond filter will NOT remove suspended algae without help from an UVC (Ultra Violet Clarifier). Most modern filters come equipped with an UVC included in the basic design. This is the best type of filter to buy.

List of All Important USA Brands of Pond Bio Filters Reviewed Here

Please review the list below. If you click the appropriate filter link you will be taken to a detailed page showing all the models available for that range along with important performance details. The range includes:

Bioforce filtersHozelock Cyprio Bioforce pressurized pond filters
These pressurized Hozelock pond filters from a leader in water gardening, Hozelock Cyprio, make hiding a filter a lot easier than when a box type gravity filter is used.
This range does not include an UVC clarifier. Cleaning of these filters is made easy by the design of the lid. Inside the filter casing is a series of open-celled foams to collect debris and add filtration surface on which bacteria grow. Sitting below the foam is the biomedia.
Bioforce UVC ComboHozelock Cyprio Bioforce pressurized pond filters including UVC
These top selling pressurized Hozelock pond filters with UVC ensure a pond is kept clean and clear all year round. Compact design and the fact they can be buried or placed remote from the pond make hiding a filter a lot easier.
An UVC or Ultra Violet Clarifier is important if a pond is stocked with fish especially in warm sunny weather. Under these conditions algae growth can be significant resulting in green or brown murky water. The UVC (sometimes also called a UV sterilizer) is designed to kill the offending suspended algae thus ensuring clear water.
Green machineHozelock Cyprio Bioforce gravity (Green Machine) pond filters excluding UVC
Hozelock Cyprio gravity flow filters go by the brand name "Green Machine" . They do an excellent job of purifying pond water but the absence of an UVC which can be bought separately means they do not control algae blooms.
This type of filter has fallen out of fashion in recent years with pressurized filters having come to the fore. The disadvantage of gravity filters is that they are bulky and difficult to hide since they have to be close to the pond or waterfall because there is only gravity to allow the water to fall back into the pond.
Fishmate filtersFishMate gravity flow pond filters excluding UVC
FishMate also known as Animate pond filters have been sold for many years and are well established and noted for good biofiltration performance on various sized ponds. One of the significant advantages of FishMate filters either gravity or pressurized is that they contain what is probably the best filter biomedia available. The name of this filter media is Supra in USA and Alfagrog in the Uk.
Oase FiltoclearOase Filtoclear Pressurized Pond Filters Including UVC
Oase is the world leader when it comes to ponds and water gardening equipment. The products are made in Germany to exacting performance standards. These Filtoclear filters have an UVC built in for a clear water guarantee. UV stands for ultra violet light and this light when exposed to algae circulating in the pond water is killed. Once dead the algae clumps together and is able to be removed in the filter
Oase BiotecOase Biotec gravity flow pond filters excluding UVC
There are 3 Biotec gravity flow pond filters in the range catering for ponds from 2200 gallons up to 13000 gallons. These filters like most box-type gravity pond filters suffer from the problem of hiding them.
They are quite large in size. They work extremely well in purifying pond water but the drawback of the bulkiness of the containing box means people are going more over to pressurised filters.
Tetra FiltersTetra Pond bio filters excluding UVC
Tetra Pond filters are low cost efficient cleaners of pond water and are available in 3 different sizes for ponds between 500 and 1000 gallons making them ideal for small to medium ponds.
The Tetra filters are very basic units but they do an acceptable job of cleaning pond water.
They do not come with a combo Ultra Violet Light clarifier/sterilizer.
Aquabead large pond filtersAquabead koi & large pond filter systems
Aquabead filters are designed for large hassle free pond keeping systems. They are sold as complete systems and are prefect for those exacting koi ponds where growth of the koi in a stress-free environment is of paramount importance. There is a filter in this range to suit any discerning pond keeper. The Aquabead Plus is the top selling Koi Pond filter and it comes pre-assembled on a skid ready for pipe connection ... followed by "all systems go".
Ultima pond filtersUltima Koi Pond bio filters
Ultima Pond filters in the Ultima series are modern filters incorporating state-of-the-art biomedia. They are low cost efficient cleaners of pond water and are available in 6 different sizes for ponds between 1000 and 20000 gallons making them ideal for small right through to medium and large ponds. Recent advances in biological bead filtration have made it possible for the average pond owner to maintain clear, healthy water year round in medium to large sized ponds at low cost.
These low maintenance systems have brought the fun back into owning a pond by eliminating the need for awkward sponge and other submersible filters that are difficult to clean.
Aquadyne Pond bio filters excluding UVC
Aquadyne Pond filters are low cost efficient cleaners of pond water and are available in 3 different sizes for ponds between 500 and 1000 gallons making them ideal for small to medium ponds.
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