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  1. #1

    What makes you choose one filter over another?

    Please bear in mind that Iím only 16 months into keeping Koi. My start out filter was the Oase biotech 36000 but as the pond is now around 20,000 litres we are upgrading to the Oase screenmatic 90000.
    We looked at the Nexus 320 and various other options but they all seemed to need a room dedicated to them and appeared to be quite complex.
    Am I missing something? It would appear that all these systems need lots of maintenance and can be extremely costly, whereas the Oase are almost idiot proof 😂. Also, I see so many of the Nexus for sale secondhand. Why would that be?
    Can someone explain the benefits of having these ďmegaĒ systems? Especially if itís just a hobby.



  2. #2
    Senior Member Rank = Grand Champion samp09's Avatar
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    Hello Denise, the main reason behind the big systems is often to hold the big bio capacity to support feeding the amount required to grow fish comfortably and not cause water quality issues. You will always find nexus etc for sale as people upgrade to the likes of drum & moving beds or closing down ponds etc but that's not because they are bad filters.

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  4. #3
    Senior Member Rank = Gosai Martin59's Avatar
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    Hi Denise.
    I have been running a nexus for 18 years now and I think it’s one of the best investments I’ve made. There not complex in any way and very easy to maintain, never had a problem with it and keeps my water parameters spot on. The only thing I would say is they don’t polish the water as much as I would like, which is why I’m going to upgrade to a drum, but I will be keeping the nexus and incorporating it in the filter system.

  5. #4
    Senior Member Rank = Adult Champion Twhitenosugar's Avatar
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    Hi Denise.

    Koi produce a huge amount of waste (as you have probably come to realise) and as they get bigger, they naturally produce even more.

    To keep koi it needs effective filtration. If there is more waste than the filters can handle, things soon go down hill very quickly.

    So people tend to over engineer the filtration. This is the case particularly as many filter manufacturers overstate how much water flow their filters can handle. So if a filter says it can handle 50,000lph flow through it. Realistically it will only comfortably handle 25-35k lph.

    The other factor is how easy they are to keep clean. Generally speaking the cheaper the filter the more effort is needed to keep them clean. As an example, you can get a multi bay filter for pretty cheap but then you have to keep cleaning out stinky sponges etc. Which is not fun in the depths of winter...

    So most people start out with cheaper filters, then realise they aren't big enough to handle all the waste or are too labour intensive and upgrade to something better suited to the job.

    Personally, the key thing to get right is mechanical filtration i.e. the physical removal of waste particles in the water. I find drum filters and sieves as being the best at doing that.

    Other filters do that as well but there are drawbacks e.g. bead filters do this but require a pump that uses a lot of electricity.

    If you can extract all the waste particles, then the biological filtration i.e. breakdown of wee, is fairly easy. E.g. a moving bed filter is a simple but effective way to do that.

    Nexus filters are pretty popular as they do both types of filtration in one unit, have no moving parts so are durable, have a relatively small footprint and are fairly easy to keep clean. The main draw back to them from what I can make out is they aren't 100% effective at mechanical filtration and so let some particles get back into the pond.

    The other consideration is how clear people want their water. If you want it crystal clear, then you will need a very effective mechanical filter plus UV filtration to kill off the free floating algae particles that are too small for mech. Filters to catch. But if you aren't so fussed then cheaper/smaller filters will do.

    Hope this helps gives some insight.

    Sent from my Pixel 8 using Tapatalk
    13,000L fibreglassed raised pond with window

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  7. #5
    That does make sense. I appreciate your response.

  8. #6
    Quote Originally Posted by Martin59 View Post
    Hi Denise.
    I have been running a nexus for 18 years now and I think it’s one of the best investments I’ve made. There not complex in any way and very easy to maintain, never had a problem with it and keeps my water parameters spot on. The only thing I would say is they don’t polish the water as much as I would like, which is why I’m going to upgrade to a drum, but I will be keeping the nexus and incorporating it in the filter system.
    I can honestly see that once my Koi get bigger that I will be looking at something like a drum filter. I don’t have any fish over 14” yet but really look forward to watching them grow.

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  10. #7
    Quote Originally Posted by Twhitenosugar View Post
    Hi Denise.

    Koi produce a huge amount of waste (as you have probably come to realise) and as they get bigger, they naturally produce even more.

    To keep koi it needs effective filtration. If there is more waste than the filters can handle, things soon go down hill very quickly.

    So people tend to over engineer the filtration. This is the case particularly as many filter manufacturers overstate how much water flow their filters can handle. So if a filter says it can handle 50,000lph flow through it. Realistically it will only comfortably handle 25-35k lph.

    The other factor is how easy they are to keep clean. Generally speaking the cheaper the filter the more effort is needed to keep them clean. As an example, you can get a multi bay filter for pretty cheap but then you have to keep cleaning out stinky sponges etc. Which is not fun in the depths of winter...

    So most people start out with cheaper filters, then realise they aren't big enough to handle all the waste or are too labour intensive and upgrade to something better suited to the job.

    Personally, the key thing to get right is mechanical filtration i.e. the physical removal of waste particles in the water. I find drum filters and sieves as being the best at doing that.

    Other filters do that as well but there are drawbacks e.g. bead filters do this but require a pump that uses a lot of electricity.

    If you can extract all the waste particles, then the biological filtration i.e. breakdown of wee, is fairly easy. E.g. a moving bed filter is a simple but effective way to do that.

    Nexus filters are pretty popular as they do both types of filtration in one unit, have no moving parts so are durable, have a relatively small footprint and are fairly easy to keep clean. The main draw back to them from what I can make out is they aren't 100% effective at mechanical filtration and so let some particles get back into the pond.

    The other consideration is how clear people want their water. If you want it crystal clear, then you will need a very effective mechanical filter plus UV filtration to kill off the free floating algae particles that are too small for mech. Filters to catch. But if you aren't so fussed then cheaper/smaller filters will do.

    Hope this helps gives some insight.

    Sent from my Pixel 8 using Tapatalk
    Thank you for going into so much detail. It really is extremely helpful. I know that any Koi I have will stay with us for life and I’m sure that in another couple of years an upgrade will be needed again. Now we just need the weather in the UK to allow us to enjoy them more

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  12. #8
    Junior Member Rank = Fry sarks's Avatar
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    Why does a bead need a pump that uses alot of electricity. I got a blue eco that is very economical and has lots of power. In the winter when I don't feed I turn the pump down so use even less electricity.
    For the power behind them they use very little compared to other run of the mill pumps

  13. #9
    Senior Member Rank = Adult Champion Twhitenosugar's Avatar
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    Due to the back pressure.

    When I say uses more electricity, I mean uses more electricity 'to obtain the same flow rate' than a filter with low resistance/back pressure.

    It's the same with a shower filter. As you need to pump the water to a height a pump will need to use more energy/electricity to achieve the same flow rate on a shower than it would on say a moving bed filter.

    Sent from my Pixel 8 using Tapatalk
    Last edited by Twhitenosugar; 13-06-2024 at 02:02 PM.
    13,000L fibreglassed raised pond with window

 

 

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