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Pumps with Needle Wheel/Fractionating Impellers - CO2, O2, and Solenoids

Discussion in 'CO2 Enrichment' started by David, Jul 25, 2012.

  1. David

    David Prolific Poster

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    Happy humpday everyone,

    I've been researching the use of pumps with needle wheels/fractionating impellers for CO2 diffusion as an alternative to using in-line or in-tank reactors or diffusers, respectively.

    I think this method would be great for me as I like to minimize tank clutter as much as possible, and I can use a pump inline with my Eheim 2215 to bring it closer to the output of my 2217 (OCD??? :highly_amused:)

    The questions I have are:

    1. If my pressurized CO2 is connected to the venturi inlet on the pump, will back-pressure be created on the solenoid when the CO2 turns off? Could this have negative consequences?

    2. Is there some sort of bypass that could allow the venturi to draw atmospheric air when the solenoid is closed for tank aeration at night?


    Cheers
     
  2. David

    David Prolific Poster

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  3. mike

    mike Guru Class Expert

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    May not be enought

    Hi David,

    I'm not sure you'll see much of an improvement in your flow by using the Mag 3. I use a Mag 9.5 with a factioning impeller and I measured about 400GPH. Right off the bat, with the fractioning impeller, you will loose flow and you also have to take into account head pressure and bends. I have 5 feet of head pressure, two 45 degree elbow and two 90 degree elbows. My Mag 9.5 is rated at 950 GPH so I'm getting less than half the flow. From what I have read the Eheim 2215 is not a very efficient pump/filter, at best you may be getting 120gph. If your lucky you may get about 150 GPH out of the Mag 3. If you want to try and match your 2217, which probably has a flow of about 230GPH, you may want to get the Mag 5.

    Mike
     
  4. David

    David Prolific Poster

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    Thanks for the wisdom. I'm going to run flexible tubing from the outlet of the Mag to my spraybar so I won't have the rigid 45s and 90s that you have with your PVC/ABS; but I forgot about headloss and the flow restrictions from the media of the 2215.

    If we assume that the ~160GPH rated flow of the 2215 translates into ~110 GPH in application (31.25% loss) then I'd apply the same to the ~260 GPH rating of the 2217 for a realized flow of ~180 GPH. The flow through the 2215 will be determined by the stronger of the two pumps; should I really assume that the Mag 3 will lose almost half of its rated output?
     
  5. mike

    mike Guru Class Expert

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    I'll get back to you tomorrow on this question, I'll do a test with my Mag 9.5. I will see what type of flow I get with less than 2 feet of head pressure using flexible hose.

    Mike
     
  6. David

    David Prolific Poster

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    Cheers Mike, looking forward to it.

     
  7. mike

    mike Guru Class Expert

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    Hi David

    I was quite surprised with what I got.

    I did the test twice. My flexible hose was 24 inches and about 6 inches was hanging down in the bucket. So the head pressure at the most was about 18 inches.

    Test 1: filled a 4 gallon bucket, It took 26.4 seconds. So that is 545 gph
    Test 2: Filled the same bucket. It took 26.7 seconds. That is 539 gph.

    The Mag 9.5 is rated at 950gph, so I'm loosing a little over 400 gph. As I had said before, my display tank is about 5 feet high at the rim and I have two 45 degree elbows (which should not effect flow too much) and two 90 degree elbows (which you may need also to get over the edge of the tank, the flexible hose may kink) and I get a little under 400 gph.

    It would be interesting to see what kind of flow can be achieved using a regular impeller.

    I doubt you'll see more than 150 gph with the Mag 3 using a fractioning impeller, probably more like 130gph

    Hope this helps,

    Mike
     
    #7 mike, Jul 27, 2012
    Last edited by a moderator: Jul 27, 2012
  8. David

    David Prolific Poster

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    Can anyone shed any light on my initial comment?

    If my pressurized CO2 is connected to the venturi inlet on the pump, will back-pressure be created on the solenoid when the CO2 turns off? Could this have negative consequences?

    Also, does this method of CO2 enrichment interfere with an attached bubble counter?
     
  9. Forumsnow

    Forumsnow Member

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    I have mine hooked up to an eheim 1103 into the Venturi and have had no problems. Just a check valve shortly after it enters and another after the bubble counter and everything is gravy. Now tue pump leaking is another story!!!
     
  10. Tom Barr

    Tom Barr Founder
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    I use a main return pump and then use a small venturi NW pump. You can take smaller powerheads and then modified them to atomize the CO2, then that mist hits the return suction and another impeller again, then travels up the 3-8 ft worth of piping........

    I need to convert a couple of my tanks over to this.

    That and seal up some of the over flows and add a vent loop to the wet/dry sump section from the prefilter.

    On my to do list for sure.
     
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