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Noisy Pump

Discussion in 'CO2 Enrichment' started by scottward, Sep 7, 2009.

  1. scottward

    scottward Guru Class Expert

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    I have my AM1000 hooked up to an Ocean Runner OR2500 external pump. I have it hooked up in 'dual venturi' mode using Tom's advice.

    With the false gas valve open so that the CO2 can be fed back into the pump, everything is flowing as it should, but it's noisy.

    When the bubbles are actually churning through, it's not too bad. But when the bubbles stop it sounds a bit like a bullfrog!

    Any idea what can cause this?

    Scott.

    P.S. I was having a problem with gas getting trapped in the top of the reactor; I figured out what this was, the tube that I was using for the dual venturi like was blocked up.
     
  2. jonny_ftm

    jonny_ftm Guru Class Expert

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    Silence / noise is something very individual. I, for my self, can't support any immersed pump running above 80 gph...

    Now, why with air it is more silent...

    Try to run it without the venturi and see maybe
     
  3. Gerryd

    Gerryd Plant Guru Team
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    Hi,

    I think your pump is too large for the reactor. The pump is rated at 625 gph and I don't think the AM1000 is rated for flow that high. Remember it is only 3/8 inlet/outlet to the reactor.

    I never used more than a 500 gph to run mine with the venturi mod and it was always very quiet.

    I can't find the rating for the AM1000 but your pump may just be too much for it.

    You can always place a ball throttle valve after the pump outlet and thus reduce what goes to the reactor. This will show if the pump is too big. Watch the reactor performance though to ensure no issues there.

    You can also add a bypass line where any flow blocked from the reactor simply flows AROUND the reactor and is plumbed back to the output AFTER the reactor outlet. This keeps the pump running optimally and uses all of the flow while allowing you to control the flow to the reactor.

    You can also try removing some/all of the bio-balls, but again watch for performance issues.

    Hope this helps.
     
  4. Biollante

    Biollante Lifetime Charter Member
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    Hi Scott,

    The AM1000 wants at least 1000 l/h (265 g/h) I don't see any maximums. I think Gerry is likely correct. Probably just too much pump.

    Biollante
     
  5. scottward

    scottward Guru Class Expert

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    Thanks for the feedback guys.

    With the pump underneath the cabinet and by measuring the head etc, I think the flow rate is reduced quite a bit. It could indeed be a little on the fast side, I suspected this once before and discussed it in another thread.

    I had a think about it last night, I think perhaps some bubbles are getting trapped in the Ocean Runner above the impeller, so there not getting chopped up, but somehow rattling about inside the pump.

    I will try changing the orientation of the pump to see if that makes any difference.

    Worse case, what do you guys think about me re-directing the dual venturi line (can't think of what else to refer to it as!), to someplace else? i.e. rather than putting it into the intake of the pump so that the mist goes back through the AM1000, redirect it somewhere else. For example, I could put the end of the dual venturi line into a seperate powerhead or even into the intake of my canister filter? Would the efficiency be just as good, or do I really need to have it go back through the AM1000 to get the benefits?

    Scott.
     
  6. shoggoth43

    shoggoth43 Lifetime Charter Member
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    I don't see why stuffing that line into another powerhead would matter much as long as you aren't getting a firehose stream out of the dual venturi line.

    -
    S
     
  7. scottward

    scottward Guru Class Expert

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    Yeah, I suppose.

    When Tom talks about increasing the efficiency of the reactor (either the AM1000, his DIY one, or something similar), is it the mist passing through the reactor and dissolving here that is the more efficient part, or it really the removal of the air gap and the reduced backpressure on the pump that is the more efficient part, or both?

    If it's the second option, I suppose it wouldn't matter if I re-direct the 'dual venturi' line somewhere else.

    I have tried shutting down the dual venturi line but get an air gap very quickly (within 10 minutes).

    Scott.
     
  8. jonny_ftm

    jonny_ftm Guru Class Expert

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    Hi scottward,

    I know that since a while you're fighting with the AM1000 and CO2 distribution.

    I won't answer your specific question on noise maybe, but, I can tell you something for sure: you'll spare so much headache, money and especially time if you try to look differently at your CO2 distribution. One of the ideas you were advised by Tom, sounds for me the best way to start: think at having 2 CO2 independent sources (you could keep same canister of course, using a cheap Y CO2 connector or a much more expensive double valve CO2 reducer). That way, you could keep your AM1000 without any ventouri and add another source with a needle wheel, a diffuser, a reactor, an inline atomizer...

    You could set it up in anyway you like. Just keep in mind that to have a good CO2 distribution in your tank, using two CO2 points of distribution will simplify your setup, reduce power usage, noise and issues with the AM1000, while still giving you a far better CO2 distribution. Adjusting the light to lowest will give a definite plus to maintain CO2 stable
     
  9. shoggoth43

    shoggoth43 Lifetime Charter Member
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    It was my understanding that the 2nd pass through the reactor after being chopped up was what helped the efficiency of the unit. It may very well be both.

    Redirecting that line to another power head might also give you that 2nd line of CO2 distribution that Johnny mentioned.

    -
    S

     
  10. jonny_ftm

    jonny_ftm Guru Class Expert

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    Probably, but for his tank size and the pump power he's putting on the Am1000, it could be better done with 2 reactors in my opinion
     
  11. scottward

    scottward Guru Class Expert

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    Thanks for the feedback guys.

    Jonny_ftm, I like your idea about splitting the CO2 outlet using a Y - one pathway can go to the AM1000 in non-dual venturi mode, and the other pathway could go to a powerhead mister or something like that.

    I tried putting the dual venturi line directly into a powerhead, but I think most of the gas ended up going to it and the AM1000 was then under utilised.

    I don't think this Ocean Runner external pump is going a very good job of misting the gas and I think there is some kind of pressure problem or something like that that is causing the noise.

    It does really sound like my best move might be to just run the AM1000 as the manufacturers intended, pumping as much gas into it as I can without running into large air gap problems, and redirect any extra gas to a powerhead that can mist the gas and whizz it about the tank.

    Would this approach be just as good as a working dual-venturi?

    Scott.

    P.S. As a side thought, I notice that the problem gets worse later in the day. Could this be because the plants have had their fill and consequently less gas can get dissolved because the water is becoming quite saturated?

    P.P.S. For people that DIY and external reactor and use white PVC, how can they tell if they have an air gap??? ;-)
     
  12. nipat

    nipat Guru Class Expert

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    Listening + try opening the upper tube (see: http://www.barrreport.com/articles/3444-dual-venturi-diy-external-co2-reactor.html )
    to see if there are bubbles getting out ;) But generally (in my case) there will always be little air build-up there,
    so there will always be some bubbles coming out of the upper tube. Anyway, as long as there are no CO2 bubbles
    coming out of the outflow (that flows water into the tank), I'd think the reactor does its duty fine so I'd not
    bother checking it (I'm not using misting method).
     
  13. shoggoth43

    shoggoth43 Lifetime Charter Member
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    The problem is likely worse later in the day as the on CO2 residual gases are not dissolved as easily and have nowhere to go except hang around building up that air bubble. The gas in your tank is never just CO2 there's always little bits of something else. If you're using DIY then my answer is completely bogus and I apologize for missing that bit.

    -
    S


     
  14. jonny_ftm

    jonny_ftm Guru Class Expert

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    I also think it is build up of gases at the end of the day (N2, HnCn...), pollution gases in canisters.

    The OR is not built to be a needle wheel, maybe there's the issue also

    I still think, that running the AM1000 alone, no mod, at its maximum capacity (you'll know when you find the bps rate at which no major build up occurs, for me, at 2-3bps, no build up at all when ran on my Eheim 2078), and with an Y, running a second solution (a needle wheel for example) is a good choice. By the way, just noted Eheim makes a needle wheel too, but too much expensive
     
  15. scottward

    scottward Guru Class Expert

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    I figured out why my pump was getting so noisy. I pulled the dual venturi line out of the intake back to the pump and had a look at the CO2 gas coming out of it. Rather than it coming out in a fairly constant stream, it was burping out periodially in large blasts. These large blasts of gas were causing the pump to run dry momentarily, which was creating a racket!

    In dual venturi mode shouldn't there be a fairly regular, steady flow of water and bubbles back to the pump? Or is it indeed meant to burp out?

    If it's normal for it to burp out like this, surely any pump connected would suddenly receive a large amount of gas and temporarily the impeller chamber would contain no water, just like what I am experiencing?

    For the moment I have shut off the dual venturi line, it's causing me too many hassles.

    Yep, I think I'll set up a Y type connector.

    A seperate question, if an air gap is building up at the top of the reactor, shouldn't this air gap continue to get bigger and bigger? Mine gets to a certain size and then stays that size (with the false gas valve closed of course).

    Scott.
     
  16. nipat

    nipat Guru Class Expert

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    I used to have a simpler CO2 reactor with clear tube. So I would chime in.;)

    Let's say your BPS is 3 (I know you in fact have it much higher:rolleyes: ).
    And a bubble require 3 min to dissolve completely. Then your reactor have to
    be able to hold at least 3 min worth of bubbles (540 bubbles) before equilibrium
    has been met.

    But if your BPS is beyond the reactor's capacity. The equilibrium will not happen.
    This is what I think, feel free to correct if I'm wrong.:rolleyes:
     
  17. scottward

    scottward Guru Class Expert

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    Solved!

    Just thought I would share this...

    I sent the impeller back to where I bought the pump from, and the store was able to get in touch with an Aqua Medic rep and get me a replacement impeller.

    I received the replacement impeller and put it in the pump.

    It's now beautiful and quiet - much, much better!

    The problem was that my original impeller was too loose on the shaft - it seems there was a batch of these dud impellers and I was one of the unlucky ones to end up with one.

    So, all good now!
     
  18. flipflop82

    flipflop82 Junior Poster

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    Hi Scottward,

    good to know that your problem has been solved. I hope you wouldnt mind my butting in with a query of my own on your thread. I had a look at Tom's dual venturi DIY reactor , and it has the both the CO2 and the water inlet at the top; wouldnt the CO2 inlet have been better at the bottom - rising bubbles pushed by water flow downwards and the undissolved CO2 will collect at the top which the very nifty venturi loop will take care of? No?


    -flipflop
     
  19. nipat

    nipat Guru Class Expert

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    Hi,

    (Not Scottward, but the quoted is my reply) the Tom's reactor's CO2 inlet tube is long, reaching bottom
    area of the reactor.
     
  20. flipflop82

    flipflop82 Junior Poster

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    Aha! That explains.

    Thanks.

    -flipflop
     
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