Multiple Pumps

Discussion in 'Filters, Filtration and Pumps' started by a1Matt, 29 Oct 2008.

  1. a1Matt

    a1Matt Member

    Messages:
    2,518
    Location:
    Bromley
    I have a 1200lph rated canister filter (Tetratec ex1200), if I add a 2000lph inline pump (Eheim compact +), what does my rated flow rate become?
    Can I add the two figures together or does that formula not work when they are inline?

    (I appreciate this will always be a simplification as I am not taking into account head height, bends, tubing diameters, media, etc.)
     
  2. vauxhallmark

    vauxhallmark Member

    Messages:
    568
    Re: Super flow!

    Can't you just leave the filter as it is and use a separate inlet and outlet for the pump? You could put any inline stuff (heater, reactor etc.) an whichever you prefer, or one on each. I'm not an engineer, but having two pumps inline with each other doesn't sound like a good idea to me, either for maximising flow, or for the heath of the pumps.

    Let us know what you come up with!

    M
     
  3. a1Matt

    a1Matt Member

    Messages:
    2,518
    Location:
    Bromley
    Re: Super flow!

    My train of thought was going the same way with regards to competing impellers. I thought I might get 2000 'and a little bit.' I also wonder if placement makes a difference - if I place the filter before my monster size reactor and the pump after it, it might reduce the 'competition'.

    I hadn't thought of removing the impeller completely though :!: This is a nice possibility to ponder... I could then get a 3000lph rated Eheim, and just leave the filter turned off. On my 160l this would give me a rated flow approaching 20x. Hmmmm.....


    I agree it doesn't sound like a good idea. I've pondered it a lot, I am not completely closed to the idea, but would prefer not to have another set of inlets and outlets in the tank though. This is mainly from an aesthetic point of view. I have thought of various wacky combinations. One of these was to have a second inlet and then combining the outlets with a Y junciton so that I have just one spraybar for the return.

    I know Sam has put an inline pump into his steup, so wondered if he has any words of wisdom on it.
     
  4. a1Matt

    a1Matt Member

    Messages:
    2,518
    Location:
    Bromley
    Re: Super flow!

    Another train of thought I have is... if I have two sets of outlets then the flow will possible compete and cancel each other out to some extent. I understand that this is not an issue with inlets. I am currently happy with my distribution, I just want to up the flow so that it gets through the density of the plant more.
     
  5. mick b

    mick b Member

    Messages:
    80
    Hi Matt,

    The pumps will compete, and dependant upon which way around, filter-load etc, and they may even cause cavitation (not good).
    Also, most cannisters have pipe and fittings, to match the impellor output, so you may not see any improvment at all!

    So IMO, (I have similar) put them on different inlets and outlets, that gives the added benifit of;
    2 places to draw in water (inlets) which creates flow ;)
    2 places for outlets, giving lots of variation to play with and the best circulation poss.

    If you do remove the impellor in the cannister (DON't plug it in as the motor coil will still be energised, even though the impellor is missing).

    HTH, Cheers, Mick B :D
     
  6. a1Matt

    a1Matt Member

    Messages:
    2,518
    Location:
    Bromley
    Thanks Mick and Mark the input is invaluable. I now see that separate inlets and outlets makes a lot more sense and I now intend to go this route.

    I'll probably get used to the sight of the extra pipework and not notice it after a while :) and I already have a couple of ideas of placements and how it might improve rather than degrade the flow pattern. I quite enjoyed experimenting with my single inlet and outlet for some time before I settled on the current position... two sets should keep me amused for ages :lol:

    So my next choice is which pump to go for...

    After a fair bit of research I have opted for the Eheim Compact range. This was done by weighing up price and wattage consumption against rated flow. ( http://www.charterhouse-aquatics.co.uk/ ... 4_137.html )

    Now I just need to pick which one... 1000, 2000, or 3000lph.

    My tank is 160L and my Tetratec is rated at 1200lph. The filter has the reactor and the heater inline. I haven't done tests to see what the acutal flow of the filter is.

    When it is filled with media, and just been cleaned the filter has sufficient flow to power the venturi loop on my reactor. But I know it is only just enough as after a few days the reactor venturi loop becomes inactive. This is not a problem as such as the reactor never reaches its capacity. However the venturi works great as an 'automated bleed valve' so it is something I would like to address.

    So I was thinking about going for the 2,000lph Eheim and having the reactor hooked up inline with it. (Leaving the heater on the filter loop.) This would give me a theoretical 3,2000lph flow\20x turnover.

    1000lph seems a bit low to be confident that the venturi will kick in.
    3000lph might be a tidal wave in the tank, or would it? (the 3000lph consumes a noticeable amount more electricity as well.)

    How does that sound to you guys? Any comments you have got are appreciated.

    Incidentally, putting the Eheim on a timer so that it only comes on with the CO2 is a possibility I like the idea of. Will be nice to give the fish a rest.
     
  7. mick b

    mick b Member

    Messages:
    80
    Hi Matt,

    The choice is yours! :D

    But IMO I would go with the additional 2000 ltr unit (but that's just IMO :oops: )

    This may not suit you, but I find, when checking the flow patterns, a few drips of malachite green or meth-blue can help ;)


    Cheers, Mick B
     
  8. a1Matt

    a1Matt Member

    Messages:
    2,518
    Location:
    Bromley
    As I have dwelled over this choice of pump for months and months I think I have lost focus somewhat. So your opinion is really apreciated.

    Fantastic - I had thought about adding something to see the flow but didn't know what. Currently I fill my reactor with air and watch where the air bubbles then go to! I have some blue coloured fungus treatment, so that might do the job...

    So, 2000lph is still the best bet at the moment. I'm going to hold off jumping in until this thread has been exhausted. Someone may come up with another idea\angle we haven't thought of yet...
     
  9. mick b

    mick b Member

    Messages:
    80
    Hi Matt,

    Just a thought, the inlet pipe size of the pumps may be the determining factor?

    If you are tight for space, to get 2 inlets and 2 outlets into the tank (bl**dy brace bars!) then you may find it's the size of the biggest inlet which will fit, determines which pump.

    No point in getting the big pump and then throttling the hell out of it, with an undersized inlet?

    Cheers, Mick B
     
  10. a1Matt

    a1Matt Member

    Messages:
    2,518
    Location:
    Bromley
    I hadn't thought of that. It is quite pertinent as well, seeing as my tank doesn't just have braces front to the back, they are all around, with just two corners cut out at the rear!

    Getting the set of inlet and outlets that I currently have into their positions took a little bit of cajoling. I'll put some planning into it. My intial thoughts are to replace the cumbersome right angled bends that I have at the point of entry into the tank with something a bit more malleable. That should help with flow as well!

    Removing the bracing is another option, but I don't have the balls for that.

    This hobby is slowly but surely making me become more proficient at plumbing! :lol:
     
  11. mick b

    mick b Member

    Messages:
    80

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