Aquatics FAQ's

  • Aquatics -  FAQ,s

  • Q. What is a Pond Filter System?
    A.   It is a system for filtering, clarifying and maintaining healthy, clear pond water in a garden pond environment. A pond filter system is made up of three main items:
    Filter – the filter works in two ways, mechanically and biologically.  Mechanical filtration means removing the solid particles that cloud the water. Biological filtration removes the pollutants that can be harmful to fish.
    U V C - an Ultra Violet Clarifier clumps together the algae that cause green water so that the filter can then remove it.
    Pump – a solid handling pump will pump dirty water into the UVC and filter. The movement of water will also introduce oxygen into the water, which is needed both by the fish and the beneficial bacteria in the pond.

  • Q. How do I install my filter system?
    A   Most filter systems are “pump fed”.  This means that the pump is in the bottom of the pond as far away from where the water returns as possible and at the deepest part.  The UVC and filter are placed together at the edge of the pond connected using the largest bore hose possible to ensure a good flow rate.  Pond water is pumped (by the pump) to the filter and UVC and then the water returns under gravity back to the pond.

  • Q   Which filter/U.V.C./pump should I use?
    A.   The deciding factor for choosing which equipment to use is the volume. The first thing to do is calculate this using the following formula:
    Average length (m) x average width (m)  x average depth (m) x 1000  = pond volume in litres
    Add on 25% if the pond depth is less than 70 cms.  Add on another 25% if the pond is in sunlight during any period of the day.   The figure that you arrive at is the size of filter that you are looking for. e.g. if the answer you arrive at is 5500 you would chose a filter with this rating. If the size of your pond falls between 2 filter sizes then always chose the bigger size as it is better to over filter than under filter.  The pump to go with the filter as a general rule is rated at approximately half the size of the physical pond volume (not the filter size chosen) and should mean that at least half the pond is filtered every hour. 
    Q. Do I install the whole system together?
    A.  To begin with you should not turn on the UVC until the filter is mature. This can take about 6-8 weeks and is the process whereby the filter is colonised by the friendly bacteria that keep the water healthy.

  • Q.  How long will it take to clear the pond?
    A.  Once fully mature you should notice a difference within one week of turning on the UVC and full clarity should be achieved in two weeks.

  • Q. How long will the UVC lamp last?
    A.    The useful working life of the lamps is 12 months. We would therefore advise that you change the lamp at the start of every season.

  • Q.  What maintenance is required on a UVC?
    A. The only thing that needs cleaning is the quartz tube. If there is a build up of limescale or algae on the tube it needs removing so the UV light can reach the water. This can be done with mild non-abrasive cleaning agents or even vinegar. 

  • Q.  What if the pump breaks down?
    A.   It is always best to have a standby pump available in the event of a pump breaking down. The standby pump can be much smaller as it only needs to produce about 50% of the normal flow to keep the filter system running.

  • Q.    What maintenance is required on a filter?
    A.    A filter will need checking from time to time to make sure weed is not clogging it up.  Apart from that it should normally be kept running 24 hours a day. You should normally clean 25% of the foams in your filter once every 2-4 weeks in pond water, as long as it is sized correctly and the pond is not overstocked with fish.  However you should only clean the foams when absolutely necessary. This is when they have become completely blocked.  The plastic media should not be cleaned, as this would risk killing of essential bacteria. A normal cleaning regime as we have just outlined would mean that you would need to change the foams after approximately 3-4 years.

  • Q.   I am experiencing a low flow from my pump or it is only working intermittently - why is this?
    · Try the integral flow adjuster if there is one
    · Check the strainer and impellor are clear of debris and limescale
    · Check rotor assembly is pushed fully into the motor body and is not damaged or worn.  Rotor assemblies need replacing periodically and can be purchased via our helpline.
    · Ensure recoil flaps are in position and free to move on their pivots
    · Check the fountain stem/head for blockages

  • Q   I am not getting any flow from my pump.
    A   Is the pump humming/buzzing? If so check above.
    If it is completely dead, check power supply, fuse and wiring. If all of these seem in order contact the Hozelock Customer Services helpline for help.

  • Q   My pump is tripping the safety RCD.
    A   Check power supply, fuse and wiring and remove any other equipment which is on the same electrical circuit to confirm that it is the pump, which is causing the fault 

  • Q   After a couple of days the flow through my Bioforce is reduced.
    A   The reason for the reduced flow is because the filter needs cleaning. Check that the filter is correctly sized for the pond. Check that the pump is not sitting directly on the bed of the pond as this can cause debris and silt to be circulated. Check that there is not an excessive build up of sludge in the pond if so clean out the pond. Try a different combination of foams e.g. 2 x coarse and 1 x medium instead of coarse, medium and fine. Note with the latest Bioforce ranges (3000, 5500, 8000 and 12000) these can be cleaned by backflushing without having to remove the lid. Refer to the instruction leaflet. Note: - Instruction leaflets can be downloaded from the website by visiting the customer services tab in the top right hand corner.

  • Q   The bulbs in my filter keep blowing.
    A   If the bulbs are blowing only every year or so then this is probably due to the age of the bulb. If they are blowing after only a short period of time then this may be due to water ingress. Check the quartz tube for cracks and also check that the O-rings are in place. Also check that the correct size pump is being used.  With a Bioforce, check that the outlet head is not cracked.

  • Q   My Bioforce or Vorton is leaking.
    A   Check the pump is not too powerful and there are no restrictions on the outlet. Check that the hosetail is intact, the seals are in place and the nut and jubilee clip is tight.  Check that all O-rings are in place.  Check that the screws have not been over tightened.

  • Q   Why do I still have green water?
    A    Check that it is actually green water and not blanket weed by taking a glass of water and checking the colour of the water. If it is clear (perhaps with small particles of green vegetation floating in it) then it is blanket weed, which needs to be treated with a blanket weed treatment. If the water is green (like pea soup), check that your pump and filter are the correct size for your pond by using our pond-sizing guide. Check that the UV bulb is working. If the bulb is over 12 months old it probably needs replacing to maintain performance. Check that the quartz tube is clean and intact. 

  • Q   Why do I have brown water?
    A    Check that the pond has not become overstocked due to growing fish as you may be asking the filter system to do too much. Check that excess build up of silt/sediment has been cleaned out. Check that soil is not running in from the sides of the pond. Also certain aquatic plant soils are very fine and can work their way out of planting baskets. Remove the plants for a while to see if this is what is causing the problem. Check the foams in the filter for shrinkage as this can cause dirty water to by pass them - change them if necessary. Fish who are hungry for food can disturb the sediment on the floor of the pond as they root around for food. Consider if they are underfed. If the pump is sat on the floor of the pond in sediment then this will be continually distributed through the pond and filter. Raise the pump off the floor of the pond by approximately 6-8 inches (15 - 20cm) This will ensure the pump does not pump sediment and gives the added bonus of providing a water reservoir should a leak occur with equipment outside the pond, as the pump will only empty the pond down to 15 - 20cm from the bottom and not completely empty it.

  • Q. My water isn’t clear and I am worried about my fish. What can I do?
    A. In reality fish don’t really mind the water being cloudy as long as the quality of the water is O.K. so you should either get your water tested by your local aquatics outlet or alternatively buy your own test kit. Make sure the test kit will test Ph, Ammonia, Nitrates and Nitrites. If you but your own test kit of the type with test tablets which give a colour coded indication of the attribute being tested then that’s all you need to decide if the water is OK.

  • Q. My Pond Vac keeps blocking up, what should I do?
  • A.  If you have Blanketweed it is better to try to pull most of this out in big clumps before beginning. You can remove a lot of Blanketweed by twisting a stick or cane into the weed as it sits on the pond sides. The pond vac is designed to pick up stones and debris particles up to 8mm. Using the open nozzle will allow larger particles to pass through. The stones shouldn’t go into the black chamber but they can build up. Remove the impellor chamber, shake it and the stones should drop out. Check the hose adaptor by removing the viewing chamber and shake out as stones can sometimes get lodged here.

  • Q. My Saturn Booster is continually in bypass mode, i.e. the red valve has risen up and allows water to go back into the pond - what should I do?
    A.  If this happens there is a possible blockage downstream of the Booster.  The filter and hose may be too small or the pump may be too powerful for the Booster. The maximum flow rate for the Booster is 8000 LPH. 

  • Q. Do I leave my pump and filter running during the winter?
    A.  The various options available to the pond keeper as the winter approaches fall into two main categories, i.e. continuation of filtration or removal of filtration. The decision is primarily determined by comparing the benefits of continuing filtration, which will help to sustain some degree of biological colony and reduce the risk of the pond freezing over, compared to the running cost and danger of low oxygen due to freezing. From a biological point of view, the continuation of filtration in a heated pond is essential. In an unheated pond, continuation will improve the speed of biological maturation at the beginning of the following season and give some protection in the event of winter warm spells. 

  • If you decide to shut down the filter systems during the winter months, we would recommend the following: -

  • · The system should be left to run for at least 2 weeks after feeding has stopped and should then be restarted Approximately 3 weeks before feeding commences in the spring.
    · Never feed your fish whilst the filter is out of operation.
    · Once removed, the filter and UVC should be thoroughly cleaned with tap water and stored indoors.
    · If removed, the pump should be cleaned and stored indoors. If the pump is a Prima it should be kept in a bucket of clean water to prevent the seals drying out and cracking.

  • If the entire system is removed, we advise that a small pump is used to disturb the pond surface or a floating pool heater is installed. This is to try and prevent the pond from freezing over to allow oxygenation of the water.
  • Q. I cant get my pond clear. I want to do a water change and start again. is this OK?

A. No this is the last thing you should do. It will give only temporary relief from the algae problem but it will soon return - usually within a week and this time will be even worse. This is because a delicate biosystem has been developing (even though you may have an alage problem the biosystem will still be developing) and adding chlorine rich tap water will kill all this off. It is better to look at why the problem persists in the first place. Things to look at are.

Can I provide some shade either by covering all or part of the pond with say a pergola or plant say lillies to give some surface shade?

Can I add some other plants to the pond. (these will compete with the nutrients that the algae are living on )?.

Is my filter system big enough to cope.? Remember your filter can never be too big - only not big enough.

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