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    Senior Member Rank = Rokusai dbs's Avatar
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    Use what I have or get something else...

    So, I have settled with a DracoDrum & Bio for my new pond (Circa 5,750g) and now looking at a skimmer, the question I would like to ask is should I utilise my existing Nexus 220 for the skimmer or sell it and get a cheap bead or a Sieve, space is a tad tight behind my new pond as I want the kit store to be as small as possible and not too imposing, the Nexus220 isn't the smallest footprint for sure, so what have you guys done please ??

    ALSO - is there a way to calculate the required pump size, I have ordered a varipump 2000 for the main BD's but not so sure on what would be best for the skimmer ??

    Thanks



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  3. #2
    You might need to keep the Nexus and get another pump or a bigger pump as 5750 gallons is about 26000 litres. Is that volume included filters and pipework or not.

    The maximum flow rate for the Nexus is 10000 lph but you probably want to be running it at a bit less than that plus you have to allow for flow restrictions and flow losses hence an extra or bigger pump?

    You normally aim to turn the entire pond volume over between once an hour to once ever 2 hours but some go for twice an hour so there's a bit of difference between the maximum and minimum flow rates required there so a variable speed pump or pumps is the way to go. It's always better to go bigger and turn the speed down than have smaller pumps running at 100% as it extends the life of the pump and can also be cheaper to run that way.

    You need to give the water enough time in the filters so the media can do it's job properly so again over spec the pumps to give you room to play with.

    Just bear in mind that you can always use Ts and valves to divert some water if you find you can drop the flow rate enough with any pump.

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  5. #3
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by Frimley Koi keeper View Post
    You might need to keep the Nexus and get another pump or a bigger pump as 5750 gallons is about 26000 litres. Is that volume included filters and pipework or not.

    The maximum flow rate for the Nexus is 10000 lph but you probably want to be running it at a bit less than that plus you have to allow for flow restrictions and flow losses hence an extra or bigger pump?

    You normally aim to turn the entire pond volume over between once an hour to once ever 2 hours but some go for twice an hour so there's a bit of difference between the maximum and minimum flow rates required there so a variable speed pump or pumps is the way to go. It's always better to go bigger and turn the speed down than have smaller pumps running at 100% as it extends the life of the pump and can also be cheaper to run that way.

    You need to give the water enough time in the filters so the media can do it's job properly so again over spec the pumps to give you room to play with.

    Just bear in mind that you can always use Ts and valves to divert some water if you find you can drop the flow rate enough with any pump.
    Thank you for the reply

    I may have lost you in what I am after, I will be getting a Solum25 drum and large bio for the bottom drains for turning over most of the water - the change I want is to just use on the surface skimmer, is a nexus 220 the incorrect thing for that so should I change it to something more suitable i.e. a sieve for removing debris, leaves and leftover food etc

    And as to your question on litreage, good point, well, the volume will be adjusted and built accordingly, and my figure above was draft guestimate for the pond only, not including pipework or filters

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  7. #4
    Senior Member Rank = Supreme Champion freddyboy's Avatar
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    Quote Originally Posted by dbs View Post
    Thank you for the reply

    I may have lost you in what I am after, I will be getting a Solum25 drum and large bio for the bottom drains for turning over most of the water - the change I want is to just use on the surface skimmer, is a nexus 220 the incorrect thing for that so should I change it to something more suitable i.e. a sieve for removing debris, leaves and leftover food etc

    And as to your question on litreage, good point, well, the volume will be adjusted and built accordingly, and my figure above was draft guestimate for the pond only, not including pipework or filters
    i have a ultra sieve 3 on my skimmmer with a 15000lph pump. does a good job.
    fred

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  9. #5
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by freddyboy View Post
    i have a ultra sieve 3 on my skimmmer with a 15000lph pump. does a good job.
    fred
    Thank you Fred, funny enough I was just looking at them online, maybe I do need to sell by Nexus and get something like that too then... What is the recommended flow rate so I know what size pump to be looking for, is it based on surface area I guess ??

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  11. #6
    Quote Originally Posted by dbs View Post
    Thank you for the reply

    I may have lost you in what I am after, I will be getting a Solum25 drum and large bio for the bottom drains for turning over most of the water - the change I want is to just use on the surface skimmer, is a nexus 220 the incorrect thing for that so should I change it to something more suitable i.e. a sieve for removing debris, leaves and leftover food etc

    And as to your question on litreage, good point, well, the volume will be adjusted and built accordingly, and my figure above was draft guestimate for the pond only, not including pipework or filters
    OK but if that's the case then maybe stick with the 20000 lph pump for the drum and get either another 20000 or 10000 variable speed pump for the skimmer line.

    Why not keep the Nexus and stick the sieve in front of it for the skimmer line. Or swap the Nexus for a sieve and bio chamber that way you could probably run a higher flow through it? Might be able to make up for what the main filtration is missing in total volume turn over rate between the 2 systems?

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  13. #7
    Quote Originally Posted by dbs View Post
    Thank you Fred, funny enough I was just looking at them online, maybe I do need to sell by Nexus and get something like that too then... What is the recommended flow rate so I know what size pump to be looking for, is it based on surface area I guess ??
    Surface area is measured in square mm, cm, m, inches or feet depending what you prefer to use but has very little to do with over all pond volume which is measured in cubic mm, cm, m or litres or inches, feet or gallons.

    OK so you need to know the surface area to calculate the volume using the depth of the pond. Well if you are building a round, square, rectangular, triangular etc shaped pond. I think that's referred to as a formal shape? if you go for an informal shape something like a banana, kidney bowl or random shape pond then to work out the volume you either have to measure it using a flow meter when you fill it up or a lot of very accurate measurements and even then it a best guess at most compared to a flow meter.

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  15. #8
    At the end of the day it's the filters that dictate the maximum flow rates. So you look for somethings that capable of flowing more than the recommended flow rates allowing for pressure and flow losses in your filters and pipework etc. So you may have to add extra filtration to get the turn over required for your pond's over all volume?

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  17. #9
    Senior Member Rank = Supreme Champion freddyboy's Avatar
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    Quote Originally Posted by dbs View Post
    Thank you Fred, funny enough I was just looking at them online, maybe I do need to sell by Nexus and get something like that too then... What is the recommended flow rate so I know what size pump to be looking for, is it based on surface area I guess ??
    30000lts an hour. Don t for get it is a mechanical filter. Not a bio filter. Mine is rmid returns to pond. So gives a good circulation of the pond. You could use it for a bakki shower. The amount of crap it takes out. Is unbelievable.
    Fred

    Sent from my SM-G960F using Tapatalk

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  19. #10
    Extreme Koi Member Rank = Hassai NickK-UK's Avatar
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    Quote Originally Posted by dbs View Post
    Thank you for the reply

    I may have lost you in what I am after, I will be getting a Solum25 drum and large bio for the bottom drains for turning over most of the water - the change I want is to just use on the surface skimmer, is a nexus 220 the incorrect thing for that so should I change it to something more suitable i.e. a sieve for removing debris, leaves and leftover food etc

    And as to your question on litreage, good point, well, the volume will be adjusted and built accordingly, and my figure above was draft guestimate for the pond only, not including pipework or filters
    The bio is calculated vs the stocking (average stocking for a pond of a particular size) production of ammonia. There's a limits to the performance - too low a flow rate and you starve the biofilm, to fast and the biofilm doesn't extract the maximum per lph although over a 6 hour period this may average out. The point here is as long as you aren't starving the bio it's ok (the more stocking - the more nutrients per litre for the fish.. the less stocking and you may need to increase the rate if you think about it to maintain the same nutrient flow). Then it's about how much you can get through your pipes not to starve the bio..

    Mechanical is more about microns and open surface area the filter has before it restricts so much that it needs to wash or in the case of a sieve - needs washing.

    A Solum 25 has a larger drum than my 16 - so it can cope with more waste.. but that 25,000lph will be clean water but I suspect will do 18-21,000lph. If you have equal 4" BD and skimmer lines into one filter you will get a 50:50 flow rate. Putting a sieve in front of the drum does not help maximum flow rate but helps maximum waste rate only.

    Going for a second loop - skimmer -> sieve ->pump->pond means you can skim the surface and still have max rate through the RDF from the BD but you add maximum flow rate.

    Trying to connect and balance two separate loops is extremely difficult (also the flows change over time).

    Some thoughts.. probably confusing but there's no 'right' answer only what is optimal for your specific pond.
    1700 litres on 50 watts
    Planned 11,777 litres on 58 watts. 1300l anoxic, 4" airlifts, Solum 16, bio.

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  21. #11
    That's kind of what I was trying to say Nick but without using so many words I thought

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  23. #12
    Senior Member Rank = Rokusai Mike Bass's Avatar
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    Quote Originally Posted by dbs View Post
    So, I have settled with a DracoDrum & Bio for my new pond (Circa 5,750g) and now looking at a skimmer, the question I would like to ask is should I utilise my existing Nexus 220 for the skimmer or sell it and get a cheap bead or a Sieve, space is a tad tight behind my new pond as I want the kit store to be as small as possible and not too imposing, the Nexus220 isn't the smallest footprint for sure, so what have you guys done please ??

    ALSO - is there a way to calculate the required pump size, I have ordered a varipump 2000 for the main BD's but not so sure on what would be best for the skimmer ??

    Thanks
    I am aiming to do something similar in my current 3200 gallon build. From 2x 4”air BDs a Filtreau Drum +35ltr k1 combi with 20,000 lph AF pump into 2 low level 2” returns. The Oase 4” skimmer will go into a Cetus sieve into a large converted vortex with fluidised K1 then 55w UV & either bakki shower &/or a 2” low level return with10,000 lph AF pump With additional bypass from the BD supply to anoxic & aquaponic systems. But this is just based on looking at a lot of people’s builds. I originally was going to use a spare Eazypod I have but not sure that would help.
    1kGal BD/Skim Drum/chamber/brush/mat/UV/k1 3.2kGal 2window 2airBD/skim Sieve/Drum&k1 alfa/anox/UV

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  25. #13
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by Frimley Koi keeper View Post
    OK but if that's the case then maybe stick with the 20000 lph pump for the drum and get either another 20000 or 10000 variable speed pump for the skimmer line.

    Why not keep the Nexus and stick the sieve in front of it for the skimmer line. Or swap the Nexus for a sieve and bio chamber that way you could probably run a higher flow through it? Might be able to make up for what the main filtration is missing in total volume turn over rate between the 2 systems?
    Thank you, I was hoping to 'get away' with a 10,000 for the skimmer just to keep the elec bill down when possible but if it needs bigger then so be it, that purchase is a few weeks off yet

    I would love to keep the Nexus but I think/hope a sieve will be better, I will not have the room for Dracko Combi, a nexus and a sieve as my kit/shed is going to only be circa 1m depth with a low roof tucked behind my long pond (currently planned at 6.5w x 2.5d x 1.6h - although these internal dimensions may change slightly)

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  27. #14
    The way I see it is a sieve is for mechanical filtration only so you are going to need something for the bio filtration after it even on the skimmer line I would think, where as a Nexus gives you both mechanical and bio filtration.

    If you look at the spec of the variable speed pumps and compare a 10000 lph to a 20000 lph you will see that if you run the 20000 lph pump at 50% or 10000 lph it will use less watts than the 10000 lph pump does running at 100% so there is a double saving there long term if you like (OK the price of the 2 pumps is different) as you are using less watts for the same flow rate and because you aren't running the pump flat out it should last longer. On top of that you still have the option to run the pump faster or slightly slower working on the principle that most variable speed pumps are adjustable between 30% and 100%.

    Obviously your budget will be the deciding factor but if you can go bigger, go bigger

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  29. #15
    Senior Member Rank = Supreme Champion freddyboy's Avatar
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    Frims right a sieve is only mechanical you need bio after the sieve.
    A sieve is a pre cleaner. Before going into let's say a nexus or bakki shower.

    On my setup I have 2 lines seperate.

    1st line bottom drain to drop in draco. Nexus 320 30000lph pump then 55 watt UV
    Then bakki shower. Top pond with plants. That's all my bio.

    2nd line skimmer to ultra sieve 3 to 15000lph pump to 55watt UV. To 2x mid returns . That's all mechanical.
    Hope that helps.
    Fred

    Sent from my SM-G960F using Tapatalk

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  31. #16
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by Frimley Koi keeper View Post
    Surface area is measured in square mm, cm, m, inches or feet depending what you prefer to use but has very little to do with over all pond volume which is measured in cubic mm, cm, m or litres or inches, feet or gallons.

    OK so you need to know the surface area to calculate the volume using the depth of the pond. Well if you are building a round, square, rectangular, triangular etc shaped pond. I think that's referred to as a formal shape? if you go for an informal shape something like a banana, kidney bowl or random shape pond then to work out the volume you either have to measure it using a flow meter when you fill it up or a lot of very accurate measurements and even then it a best guess at most compared to a flow meter.
    Ahhh yes, no problem I know the cubic capacity, what my brain was trying to work out was the following...

    If my main pump dialled down is circulating the main body of water say 13,000 per hour so turns over the whole pond in 2 hours, what does the skimmer need to do... in that, 2 scenario's, if the pond was 10 x 2 x 1.6 deep there would be 20m2 of surface water to skim, yet the same volume of water if the pond was deeper would have a smaller surface area to 'skim off' eg a pond 6.4 x 2 x 2.5 deep would only have the surface area of 12.8m2.

    Hmmmm hoping I have explained that correctly

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  33. #17
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by NickK-UK View Post
    The bio is calculated vs the stocking (average stocking for a pond of a particular size) production of ammonia. There's a limits to the performance - too low a flow rate and you starve the biofilm, to fast and the biofilm doesn't extract the maximum per lph although over a 6 hour period this may average out. The point here is as long as you aren't starving the bio it's ok (the more stocking - the more nutrients per litre for the fish.. the less stocking and you may need to increase the rate if you think about it to maintain the same nutrient flow). Then it's about how much you can get through your pipes not to starve the bio..

    Mechanical is more about microns and open surface area the filter has before it restricts so much that it needs to wash or in the case of a sieve - needs washing.

    A Solum 25 has a larger drum than my 16 - so it can cope with more waste.. but that 25,000lph will be clean water but I suspect will do 18-21,000lph. If you have equal 4" BD and skimmer lines into one filter you will get a 50:50 flow rate. Putting a sieve in front of the drum does not help maximum flow rate but helps maximum waste rate only.

    Going for a second loop - skimmer -> sieve ->pump->pond means you can skim the surface and still have max rate through the RDF from the BD but you add maximum flow rate.

    Trying to connect and balance two separate loops is extremely difficult (also the flows change over time).

    Some thoughts.. probably confusing but there's no 'right' answer only what is optimal for your specific pond.
    Excellent, thanks Nick

    Yes it has helped me in that fact that it is not simple, my next thought was to maybe put a sieve through the main before the Drum, but as you say that may not help flow.... so maybe.

    • 2 aeriated bottom drains > Drum/Bio > 110v UV > 2 returns at various levels
    • Skimmer > Sieve > return via blade


    The above would allow me to keep a smaller footprint rather than keeping the nexus after the sieve, albeit not perfect with no bio on the skimmer line, would the combination of the 2 be good enough with the skimmer taking the biggest debris then mixing the sieved water back in to be washed by the Drum/Bio

  34. #18
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by Mike Bass View Post
    I am aiming to do something similar in my current 3200 gallon build. From 2x 4”air BDs a Filtreau Drum +35ltr k1 combi with 20,000 lph AF pump into 2 low level 2” returns. The Oase 4” skimmer will go into a Cetus sieve into a large converted vortex with fluidised K1 then 55w UV & either bakki shower &/or a 2” low level return with10,000 lph AF pump With additional bypass from the BD supply to anoxic & aquaponic systems. But this is just based on looking at a lot of people’s builds. I originally was going to use a spare Eazypod I have but not sure that would help.
    That does sound perfect Mike, and if I had the space that is what I would do....

    Maybe I need to make more space, I was trying to keep the new pond in a smaller footprint than my current pond (Current is 'irregular kidney' circa 3.6m x 9.2m) so my new 2.5 x 6.5 internal dims (in reality footprint of 3.1m x 7.1m allowing for concrete block and hefty celotex (Celotex is my next puzzle, currently allowing for 100mm but think that may be excessive )

  35. #19
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by Frimley Koi keeper View Post
    The way I see it is a sieve is for mechanical filtration only so you are going to need something for the bio filtration after it even on the skimmer line I would think, where as a Nexus gives you both mechanical and bio filtration.

    If you look at the spec of the variable speed pumps and compare a 10000 lph to a 20000 lph you will see that if you run the 20000 lph pump at 50% or 10000 lph it will use less watts than the 10000 lph pump does running at 100% so there is a double saving there long term if you like (OK the price of the 2 pumps is different) as you are using less watts for the same flow rate and because you aren't running the pump flat out it should last longer. On top of that you still have the option to run the pump faster or slightly slower working on the principle that most variable speed pumps are adjustable between 30% and 100%.

    Obviously your budget will be the deciding factor but if you can go bigger, go bigger
    Damn... well yes great thinking and thanks, the room for kit is more limited than budget is, although area required can be made bigger, in fact yes I may move it forward a tad to give more depth tor storage.... but yes I agree I want to 'this time' buy once for the long term, so likely another 20000 on the order list, though the first is ordered an EA, I am thinking whether to try a different brand on the skimmer line or keep some similarity on the kit and grab another EA varipump .

  36. #20
    Senior Member Rank = Rokusai dbs's Avatar
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    Quote Originally Posted by freddyboy View Post
    Frims right a sieve is only mechanical you need bio after the sieve.
    A sieve is a pre cleaner. Before going into let's say a nexus or bakki shower.

    On my setup I have 2 lines seperate.

    1st line bottom drain to drop in draco. Nexus 320 30000lph pump then 55 watt UV
    Then bakki shower. Top pond with plants. That's all my bio.

    2nd line skimmer to ultra sieve 3 to 15000lph pump to 55watt UV. To 2x mid returns . That's all mechanical.
    Hope that helps.
    Fred

    Sent from my SM-G960F using Tapatalk
    Ahhhh cool, thank you.

    It looks like I may have suggested similar to yours above, so Drum/Bio/110-UV on the BD's and just Sieve on the Skimmer.. so 1 doing clean and bio and 1 skimming crap only.

    I could put a UV on the skimmer line (Have a spare 55w) but want to keep the running costs down so hoping the 110 on the BD's is sufficient ..

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