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Aeration
Even though there is an exchange of carbon dioxide for oxygen at the water surface, this is not quite enough for optimum fish keeping conditions nor high stocking rates. For fish to thrive, the oxygen concentration should be at least 8 mg/1.
toxic gasses tend to be concentrated in "bottom" water, and when this water is circulated using either a submersible pump, most of the gasses expelled when the circulated water re-enters the pond. To create effective aeration, the water reentering the pond should do so with a minimum fall of 0,6 metres. The spray-bar in the bio-filter eliminates this requirement to a degree. By installing a venturi in a return line to the pond, the aeration and resulting water quality is vastly improved.
The pond water, which incidentally should have a pH of between 6,7 and 7.8 should be circulated every 75 - 120 minutes. For example, if the total pond system contains 3000 litres, then the pump would have to deliver 25 - 40 litres per minute at the head to which the water is being pumped. Biofilters are colonised by millions of aerobic (oxygen loving) bacteria is therefore vital that the pump providing water to the biofilter is run continuously - i.e 24 hours a day!
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Removal of Settle Solids
The Pond Itself acts settling Chamber. Solids that settle out include fish droppings, leaves, insects, dead algae and sediment. These settled solids produce niters and ammonia for some time until they disintegrate to form and inert sediment at the bottom of the pond. These settled solids should be removed regularly to reduce the concentration of chemical pollutants resulting from the bacterial breakdown of the solids.
Here are three main methods of removing settled solids.
These are:
A)By vacuum. This can be achieved by using a hand operated vacuum, or by attracting a “Kreepy-Krauley” type hose to your external pump and pumping the dirty water waste.
B)By Siphoning. To be able to siphon, the water level of the pond must be higher than the point to which is being siphoned. The hosed should be at least one inch in diameter. Suction must be created at the lower end so that the flow can begin.
C)Bottom drains; This system is essential for keen Koi keepers and is only really viable if incorporated at the building stage of the pond. It only costs a little and I by far the best system. The illustration below details a simple design for the incorporation of bottom drains.
Removal of Suspended Solids
The removal of suspended solids results in clear water. Achieving clear water is probably the most sought after objective amongst most fish keepers and this is achieved by mechanical filtration. Of prime importance is the ease of maintenance of the filter without disturbing (Or Destroying) the useful bacteria.
The ECONOMY RANGE of biofilters incorporates 3 layers of foam to provide mechanical filtration.
Unlike gravel and some other filter media, open cell foam is designed to block – but then it is easy to clean. Foam should also not be cleaned too thoroughly – foam a clarity viewpoint it is better to clean moderately only when the filter overflows.
Clarity can be rapidly obtained by placing a layer of fine, sifted topsoil up to 5 mm thick over the water has cleared. The soiled serves two purposes – the foam is given a pre-coat , thus allowing it to stop very fine particles. And the biological maturation of underlying media is speeded by the presence of a large population of nitrifying bacteria in the soil. This step is, however, not really necessary as the foam becomes operational on its own quite soon ( 3 – 4 weeks ) after initiating the biofiltration system.
The SUPER VORTEX range of biofilters utilizes centrifugal torce in spiral flow pattern to facilitate most of its mechanical filtration. Additional mechanical filtration is achieved by upward flow pattern though modern media such as brushes. The vortex chamber can be incorporated to supplement the ECONOMY range of biofilters
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Every water garden is different, each one incorporating special features and ideas. A wildlife pond will probably be situated in a shady damp corner of the garden, while a koi pond may well be best positioned where you can see the fish swimming around in it. But what ever size, type or location of a pond, it must be designed around certain criteria. The availability of garden space or the types of fish to be kept in the pond are just two examples. People who keep koi in their ponds must provide the best possible conditions for them, so that they remain healthy and their owners can enjoy them at their best all year round.
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Designing a Koi Pond
Installation a koi pond in a garden is a large and costly step, and there are many points to consider when designing such a pond as part of your water garden. Koi pond design has developed rapidly over the last few years and new ideas continue to come along on a regular basis. Give careful thought to choosing the effect you wish to create and how to achieve it. Mistakes can be expensive to put right and time spent at the planning stage will pay dividends in the long run. A koi pond can become the centrepiece of a garden or be an integral part of it, blending into the landscape. Much will depend on the land available and the koi you intend to keep. Bear in mind that in good conditions, koi can grow to 75cm (30in) or more and when well fed, often out grow their pond after a few years. Large filter systems are therefore essential and, whether placed in or above the ground, will take up further garden space. There are some concepts that should be designed into every koi pond to ensure that it runs efficiently.
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Garden Aspects
To help you choose the best site for a koi pond, let us consider various garden aspects. A site facing away from the sun is probably the worst option. During the winter months, the sun is much lower in the sky than in summer and will be behind the house for much of the day. As a result, a great deal of shade is thrown on the pond, which will only be in complete full sun for a relatively short period in high summer. To get the maximum benefit from the sun's warmth in this garden, place the pond further away from the house and be prepared to provide additional water heating. The garden facing the sun is the opposite case. Subject to the position of adjacent properties or large trees, the pond will generally be in full sun all day, all year round, and additional water heating may not be required. However, you may wish to use a heater to minimize day to night swings, particularly if the pond holds a smaller volume of water that is prone to following ambient temperature.
In a west-facing garden in the Northern Hemisphere, once again the sun is a lot lower in the sky during winter months. However, this is not as critical as the 'away from the sun' case, because you will only notice the shade in the morning during the winter, and less so in the summer, when the sun is higher in the sky. This means that a pond placed near the house should still receive plenty of warmth from the sun. Once again, the opposite applies in an east-facing garden, with sun on the pond all year round and shade in the evening.
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A Quarantine Pond
It is well worth considering a second pond for quarantining newly acquired koi. Quarantine minimizes the risk of introducing disease or parasites into the pond. A quarantine system, preferably covered, can double up as a treatment area when an established fish needs medical attention. Because some disease problems will not show themselves below certain temperature levels,its temperature must be controlled.
This pond must be biologically filtered and of sufficient volume to hold the largest koi for some weeks, maybe months, without it becoming stressed and suffering further distress instead of recovering. If you intend to build one of these systems, do not overlook the question of its position and the space it will occupy before firming up on the location of the main pond. It should not be too close to the main pond to prevent cross-infection. When not built in its own 'house', some form of cover should be considered to prevent koi jumping out and predators getting in.
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The Electricity Supply
A modern pond requires a protected electricity supply, with sufficient capacity supply, with sufficient capacity to run circulation pumps, air pumps, electric water heaters, vacuum pumps, ultraviolet clarifiers and lights, etc. It must be laid to the site of a suitable dry service chamber, often known as a 'pump house'.
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The Water Supply
You will need a supply of fresh tap water from the main, preferably on its own ball valve and maybe with its own dedicated water purifier. This way, you can top up water levels and carry out water changes without a hosepipe.
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Disposing of Foul Water.
Once the pond is up and running, you will need to be able to dispose of foul pond water.
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Pumped Returns and Waterfalls
Below the waterline pumped returns are useful features in the koi pond. They assist circulation, reduce surface disturbance when viewing the fish and prevent excess cooling of the water in colder months. However, poor positioning of these returns will cause a break-up of the circulatory flow and may lead to a build up of detritus in quite spots.
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Positioning a Surface Skimmer.
At this stage, it is also important to look closely at the position of the surface skimmer. If you place it too close to a water return, it could prove useless.
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Pumps
Pumps for koi ponds can be either submersible or external. External pumps can be subdivided into suction, circulation, or pressure types. Whichever you choose, make sure it is powerful enough for the task it is to perform. The simplest task that a pump is required to undertake is either to pump water into an above waterline filter system or pull the water through the filter and pump it back to the pond. If there is to be an extra loading, such as feeding a high waterfall, you will required a more powerful pump.
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Water Testing
Once there are Koi in the pond, the water will become polluted by ammonia produced as waste from gills and anal vent. As time passes, algae and other aquatic plants will decompose and cause further pollution. Water testing is therefore the most important task that a Koi keeper undertakes.
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Ammonia (NH3/NH4) LEVELS
The presence of ammonia can seriously damage gill filaments, making the absorption of oxygen from the water difficult. It also reduces the fishes’s ability to control osmotic balance. Exposure to any quantity of ammonia is undesirable, and prolonged exposure, even low levels of ammonia, can result in the death of Koi.
Toxicity of the free ammonia (NH3), Part of the total ammonia (NH3 + NH4), increases as water becomes both warmer and more alkaline (i.e. fish can only tolerate smaller quantities of NH3 as temperature and PH Rises). You should therefore take the temperature of the water and monitor PH Levels when you test for ammonia. To reduce the risk of health problems, aim for a test kit reading of zero total ammonia in pond water.
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Nitrite (NO2) Levels
Nitrite is just as toxic as ammonia. It affects the oxygen –carrying capability of the blood. Because it also irritates their skin, Koi may jump of the3 water and flick or rub themselves on the pond bottom or walls. These are symptoms of high nitrite levels and if exposed to them for a prolonged period, Koi will become listless and die.
Keep nitrite to an acceptable level by carrying out water changes to dilute it. Continue daily water changes and testing until zero nitrite has been reached. As with high ammonia levels , reduce feeding during this time to cut down the load on the developing filter biomass.
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Nitrite (NO3) Levels
This is the end product of the nitrogen cycle. Although it is less toxic than ammonia or nitrite, do not allow the nitrite level to exceed 100 mg/l and aim for a reading of 50 mg/l or less. A separate vegetable filter ( a planted pond) can help to reduce nitrite levels . A planted watercourse will take up nitrite and phosphate (another fertilizer) from the water and may help to reduce the amount of filamentous algae present in the pond.
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Removal of Nitrites and Ammonia
Nitrites and ammonia are produced by metabolising fish decaying organic matter e.g. uneaten food, fish droppings, dead bacteria leaves, dead insects etc. These chemical compounds are toxic to fish, and for fish to thrive, their concentrations should be maintained below 0.02 mg/litre for ammonia and 0.1 mg for nitrites
Biological treatment of pond water removes nitrites and ammonia, or rather converts them to relatively harmless nitrites by bacterial action. Unlike nitrites and ammonia, these nitrites are easily absorbed by plant life. When there is a high stocking rate fish , combined with little or no plant life in the pond, then 5 -10 % of the water should be changed weekly to prevent the build up of too many nitrates.
The actual conversion of nitrites and ammonia to nitrites is achieved by two groups of bacteria, namely Nitrosomonas and nitrobacteria. These bacteria are aerobic , and are found almost anywhere where decaying organic matter and oxygen are present.
The problem however, is that there are not sufficient bacteria present in the pond itself, and it is therefore necessary to provide a medium with a high specific surface area to house a large colony of bacteria. The biofilter should allow for an even for an even flow of filtered water through the medium housing the bacteria.
When pond water is detoxified, fish have healthier appetites and this results in a much faster growth rate. In biologically filtered water, Koi, fort example, can grow from 8 cm to 30 cm in one year! Fish will also exercise more, and in general be much healthier. Disease resistance will improve, as will coloration.
Maturation of the biofilter can be accelerated by adding BIO VITAL to the pond water. BIO VITAL also has a probiotic effect on the water, Thus reducing the treat of bacterial disease, whilst boosting the water quality, and improving the health and performance of fish in the pond.
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Dissolved Oxygen (O2)
Koi prefer higher rather then lower water temperatures to ensure that their immune and digestive systems are running as close as possible to optimum level. When the water temperature is about 24 C ( 75 F), they eat well and any external skin damage heals quickly , particularly when all other water parameters are good. However, it is also the case that higher the temperature, the less oxygen the water can hold. This is significant because Koi require large quantities of dissolved oxygen in their blood to help them digest their food properly. If temperature rise too high, the fish will naturally reduce their intake of food.
But this is not the only reason for ensuring that there is enough oxygen in the pond.
The Clear Water Biofilter System
Clear water Biofilter has developed 2 ranges of filters – the ECONOMY range and SUPER VORTEX range.
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The Economy Range
The illustration below details the basic design of the ECONMOY range of filters.
The ECONOMY range is well suited to garden ponds up to 18,000 litres, and where the responsible owner can keep an eye on the maintenance of the system.
Economy Range:
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Model
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Box Size
L x W x D
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Pond Size Litres
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Max. Pump Volume Through
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CBO
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310 x 250 x 415
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0 - 750
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8 -10
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CB1
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550 x 325 x 510
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750 - 1800
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15 - 20
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CB2
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660 x 355 x 700
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1800- 2500
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20 -25
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CB3
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660 x 660 x 700
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2500 - 5000
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40 - 50
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CB4
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960 x 660 x 700
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5000 - 7500
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60 - 75
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Installation Options:
The biofilter container has been designed to be buried. Although the box itself is manufactured from robust, UV stabilised polyethylene, the sides on the larger boxes tend to want to bulge slightly when the box is full of water. The outward pressure on the sides of the box by the water is tremendous, and if the box is not buried, it might bulge and the water might be allowed flow around the foam instead of being forced through it. It is therefore important that box be buried, and the soil around the box must be very well compacted to prevent possible bulging. Just as important, by buying the box, it helps to retain the aesthetics of water feature.
It for whatever reason it is impossible to bury the box, an arrangement using brackets bolted together will prevent bulging, the illustration below details some of the typical installation options of the ECONOMY range.
Next Door Location:
In a situation where the biofilter requires a maximum of 40 litres per minute \, but the pump is delivering a flow rate of, say 90 litres per minute , but the pump is delivering a flow rate of, say 90 litres per minute ( for a large waterfall) then the following pipe work would be recommended.
By - Pass
In all installation situations it is import6ant to remember that is gravity- feed back to the pond, and that the pipes ( 40mm) returning the water from the filter to the pond should have at least a slight download slope towards the pond.. This is particularly important when the remote location is used.
Attempts should always be made to hide the box (with plants for example) so that the water feature still remains attractive. The pump should be located at the end of the pond to the biofilter return, as this creates a desirable cross flow in the pond. To prolong the life of the pump and to help with clarity, the pump should always be placed on a brick away from the lowest point in the pond.
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Maintenance
If a biofilter is being installed for the first time, it is not always necessary to clean the pond out and refill it with clean water, excepting in cases where the bottom of the pond has accumulated a lot of dirt and sediment.
When everything has been installed correctly and everything checked it’s time to switch the pump on. It is important to adjust the flow through the biofilter to the recommended flow rate. An easy way of checking the flow rate is to use a 10 litre bucket and time how long it takes to fill. Adjust accordingly.
The dirty water flowing into the filter box will begin to block the foam. All that required is to look into the box 2 or 3 times a week and to check the water level inside the box.
The only time any of the foams need to be washed is when the water level rises in the box and overflows through the overflow pipe. Even if the foams look dirty and the water level rises in the box but not overflowed yet, do not wash the foams. The aperture size of the foam is larger then a single –cell algae, and if all three foams are kept absolutely clean, this algae will pass through the foams leaving your water green.
The foams should be washed under a tap or with a hose, taking care not to tear them, but to rather squeeze them until most of the dirt is out.
When replacing the foams, ensure that they are tucked securely into the channel so that the water cannot flow around them. Filtration must be continuous i.e. the pump must run 24 hours a day
In the event that filters are not operational for 8 or more hours, the filter should be thoroughly cleaned out before the pump is switched back on.
Twice a year, the contents of the filter box should be removed. Rinse the biorings with clean pond water and put everything back as before.
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The Super Vortex Range
The Super Vortex range of biofilters has been developed for the serious Koi keeper. It is based on the most up-date-date biological filtration technology available, together with serious consideration for cost-effective efficiency and flexibility.
Most biofilters are designs to trap and decompose solid waste. This solid waste does not disappear, but is converted into soluble pollutants which add to the workload of the filter. Algae thrives in this nutrient-rice ‘soup’
The over riding principle embodied in the design of the SUPER VORTEX range of biofilters is the easy removal of this ‘BIOLOGICAL SOUP’ before it up the media and continues to breakdown producing additional ammonia etc. By removing this Biological Soup consisting of fish droppings, uneaten food, dead bacteria, leaves, algae etc, before it reaches the filter media, the efficiency the media and the attached colonies of bacteria are greatly enhanced.
This range of biofilters is based on the modular vortex system, thus being flexible enough to cater for different stocking rates, media characteristics and installation options.
The MINI VORTEX range is suitable for pond volumes of 5000 to 30,000 litres. Each MINI Vortex is 1, 25 metres high and has a diameter of 800 mm. The MAXI Vortex range is suitable for pond volumes of over 20,000 litres. These vortexes are 1, 6 metres high and have a diameter of 1, 1 metres.
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The Vortex Principle
Water containing solid waste is fed from the bottom drains in the pond, via the discharge box, to the vortex chamber. This water enters the chamber at a tangent and induces a circular flow pattern in the Vortex chamber. The denser solid waste moves towards the wall of the chamber by centrifugal force. A layer of slower moving water, caused by friction with the chamber wall, is created at the wall. Solids that are centrifugally forced into this layer will spiral downwards and settle at the bottom of the cone – ready to be flushed to waste. The majority of the vortex action takes place in the lower part of the Vortex chamber where there is no filter media to interrupt the circular flow pattern
After the vortex, the clear water, containing mainly chemical pollutants and some of the finer solid wastes, will move up through the media (brushes, etc) to the next vortex for further treatment. Light, high specific surface area and easy0clean media such as brushes are recommended for all chambers.
Any media can be used in the media chambers, depending on individual tastes, requirements and budget. All components of this system are available separately if required.
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Modular Combinations
A combination of a maximum of 3 chambers can be coupled together in series. Any number of these combinations can be installed in parallel, depending on the efficiency and effectiveness required. This will depend on a multitude of different factors some of the following: - volume of the pond, fish stocking rate, efficiency and surface area of the filter media used, feeding rate, water temperature, etc.
Below are detailed the various combinations and associated pump flow rates for
various pond sizes.
Combinations in parallel can be used for any size pond provided cognizance has been taken of stocking rate, media characteristics, feeding rate, etc. Improved performance can be achieved by substituting inefficient media with, say brushes, or by adding an additional media chamber.
Installation Options
The illustration below detail 3 different installation options for the Vortex and media chamber combinations.
a) Gravity Feed
This is by far the BEST installation option
It is far more efficient than the pump feed option because none of the solid waste is fragmented by the pump impeller, thus facilitating easier settlement. Also, the return water can enter the pond via a venture, thus improving aeration.
b) Pump Feed
The feed to the vortex should incorporate a length of approximately 1,5 m of 110 mm PVC pipe to slow the water down and thus improve the settlement efficiency of the vortex
c) Dual Feed
This option is suitable where the installation of the vortex is for the purpose of improving the efficiency of the economy range or a home built filter, Most external pumps deliver large volume water. The feed to the Vortex should be regulated to 160 lpm for the Maxi Vortex or 120 lpm for the Mini Vortex.
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Installation Instructions
Once the combinations and installations option has been decided upon, the following installation procedure should be followed
First, select the appropriate site and dig the required size hole, taking cognizance of the desired water levels in the chamber should be 30 mm below the lip when the pond is at its ideal level. Ensure that the soil at the bottom of the hole is well compacted and check the desired levels again. Place the chamber lid securely on the chamber to prevent any distortion and position the chambers accurately, ensuring that they are level before carefully gluing the connecting pipe work as well as the flushing pipe work. Clear silicone glue should be used to ensure a good seal between the chamber inlets/ outlets and the “O” rings in the 110 mm PVC pipe connections. The highest point of the flushing pipe work should be at least 200mm below the desired water level in the chamber.
Using dry river sand, back fill the whole up to the top of the cone section of the Vortex and compact this very well. At this point the system can be switched on to check the levels and for any leaks in the pipe work. The remainder of the hole can now be filled and only lightly compacted. This is to prevent any distortion of the Vortex.
Maintenance
The vortex chambers are designed to trap most of the solid waste before it gets to the media where it would continue to breakdown producing chemical pollutants. It therefore makes sense to flush the Vortex daily. The pump can be either on or off. To flush, open the ball valve in the flushing pipe work and flush the solid waste away. Continue for only a few seconds until clear water emerges.
To flush the media chambers, the pump should first off. In the case of a media case of a media chamber containing brushes, the brushes should by agitated to dislodge any waste adhering to them, and a few minutes should be allowed for the dirt to settle at the bottom of the cone. Flush to waste as with the Vortex. Other media can be “stirred” with a stick and once the solid waste has settled at the bottom of the cone, it too can be flushed to waste. Flushing of the media chambers should take place at least weekly. The flushing frequency will however, depend on many factors including stocking rate, water temperature, feeding rate, media characteristics etc.
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How to select the right filter
The first thing to do is to do is to establish, as accurately as possible, the volume of your pond. This is done by multiplying the average depth(m). The answer is then multiplied by 1000 and this will give you your volume in litres .
Both the Economy range and the Super Vortex range are flexible in their flexible in their applications so that if one, for example, decided to increase their stocking level substantially. One would only have to add another filter or media chamber from the relevant range
Remember – a good Koi keeper knows how to keep good water
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