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Thread: Flow rate query

  1. #1

    Flow rate query

    I have two 4 inch bdís on my pond and wondered how many litres per hour these can handle as Iím finding my rotary drum filter runs dry after an hour or so with both my 30k pumps on full speed; even though theyíre working to a head height of 1.5m Even if I turn one down to 50%, the drum runs dry after only a couple of hours.
    Any help/ suggestions appreciated



  2. #2
    Senior Member Rank = Mature Champion RS2OOO's Avatar
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    Is this a new or recent problem that only just started to occur?

    Are you sure there isn't a biofilm or limescale build up on the drum mesh?

  3. #3
    Itís a new set up so donít think so . Iíve jetwashed the drum to remove any factory film and Iíve purged bdís and got rid of all blanket weed a few weeks back to ensure bdís flow well.

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    Senior Member Rank = Mature Champion RS2OOO's Avatar
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    Hmmm.

    Can't really help in that case. My single bottom drain with only a finger sized gap between pond floor and drain cover easily copes with the pump set to 20k lph. The limiting factor in my case is the (small Draco 2) drum which cleans itself every 6 minutes if I increase flow to 20k lph, and cleans every 30 mins or so (at this time of year) at 10k lph.

  5. #5
    Hmm that has me thinking as the dirty side was full justvthe central drum chamber running dry which suggests a fault in the drum somewhere . Iíll try another jetwash of drum see if that helps . As it canít be the flow rate of bdís if dirty side is filling can it ???

  6. #6
    Senior Member Rank = Mature Champion RS2OOO's Avatar
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    Yep.... If dirty side is full then the restriction is between dirty and clean sides.

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    Quote Originally Posted by RS2OOO View Post
    Hmmm.

    Can't really help in that case. My single bottom drain with only a finger sized gap between pond floor and drain cover easily copes with the pump set to 20k lph. The limiting factor in my case is the (small Draco 2) drum which cleans itself every 6 minutes if I increase flow to 20k lph, and cleans every 30 mins or so (at this time of year) at 10k lph.
    How you getting on with the Draco RS?

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    Senior Member Rank = Mature Champion RS2OOO's Avatar
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    Quote Originally Posted by Scamp View Post
    How you getting on with the Draco RS?
    All good thanks scamp. It has been trouble free and keeps pond clear. Bit nervous about going on holiday and leaving it but fingers crossed it will be fine.

    Sent from my Pixel 2 using Tapatalk

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    Senior Member Rank = Mature Champion RS2OOO's Avatar
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    78 minutes between cleans this morning.

    Sent from my Pixel 2 using Tapatalk

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    Quote Originally Posted by RS2OOO View Post
    78 minutes between cleans this morning.

    Sent from my Pixel 2 using Tapatalk
    Thats pretty good! I've gone 3 years now on holiday, and all been fine. But like you nervous..anything mechanical/electrical and to do with ponds is always a chance of blockage. That said its a chance, whereas with the Nexus pre Draco it was almost a certainty of an issue over a holiday! I just make sure there is no blanket weed/treat way before holidays so all the dead stuff is through the system, and also slow flow rate down which I can do with the variable pump..all the best. Sorry Steve for hi-jacking thread..

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  15. #11
    Extreme Koi Member Rank = Grand Champion john1's Avatar
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    Hi Steve, Thinking about your problem, what drum is it and how many ltrs is it supposed to cope with?
    Is your float switch set ok?
    Are you pulling water too much?
    Put your hand into the drum behind the mesh ( with drum off ) and pour some water over the top of the mesh to see if it's getting through,only a suggestion
    Are the jets cleaning well?
    John

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