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Plumbing Needle Wheel Inline

Discussion in 'CO2 Enrichment' started by eyebeatbadgers, Aug 31, 2008.

  1. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    I finally pulled the ugly pump out of my tank, and threw it in the stand. Here's a childish diagram showing how it's set up. My question is, will this pump (Gen-X 1000lph) starve the canister, and if so, will I need a ball valve, or perhaps larger diameter hosing?

    [​IMG]

    [​IMG]
     
  2. Gerryd

    Gerryd Plant Guru Team
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    Hi Dan,

    1. Shouldn't the needle wheel connect to the reactor somehow? You have it feeding of the intake. I would filter the water first and then push it to the c02 reactor.

    The pic seems to show the needle output plumbed in AFTER the reactor??

    So you are taking unfiltered water to the reactor and then back to the tank? This does not seem optimal to me.

    It seems that the needle wheel should be plumbed into the canister output. This will send clean c02 enriched water to the reactor.

    A ball valve or two is always a good thing.

    Not familiar with your pump so cannot say about starving the can.
     
  3. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    The reactor is not in use, it simply houses my heater. Sorry I didn't clarify that :)

    I would have simply installed the needle wheel pump after the filter inline, but have heard that placing a pump in such manner would cause cavitation.
     
  4. jeremy v

    jeremy v Guru Class Expert

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    Eyebeatbadgers,

    You most likely couldn't have any issues with cavitation even if you tried. Any small mag drive type pump, powerhead, etc. that has the type of prop housing that allows for the impeller to spin either direction to create its' flow is too inefficient to ever generate the vacuum needed within the housing to cause true cavitation. You pretty much need to get into a true centrifugal pump that has an impeller and housing that is shaped just like an automotive turbocharger before the pump itself can create the intake vacuum necessary to cause cavitation. Even with a true centrifugal pump, most high volume/low head pumps would have a hard time causing cavitation, because they just aren't strong enough. You need to get into the medium and high head pumps before cavitation can really become an issue.

    With all the smaller pumps like mag drives and like yours, plumbing that is sized too small on the intake or output side of the pump will only cause decreases in flow and that's it. An undersized intake will still cut system flow more than an undersized output however, that fact remains consistent for all pressure pumps.

    Gerry is right, you are just pulling unfiltered tank water through your CO2 needle pump, but there is nothing inherently wrong with that. Your filtration ability will just remain exactly what it was before you added the needle pump, but the needle pump is increasing the total system flow and adding more circulation to the tank. You basically just did the equivalent of adding a powerhead to the tank to add circulation and diffuse CO2, but you mounted it in a way such that the powerhead doesn't actually have to sit in the aquarium.

    I think you would gain a noticeable flow increase out of both your needle pump and your canister filter by increasing the intake pipe size from the tank to the "T" where the needle valve and canister intake lines split from each other. Just going up one pipe size should be fine. That will be your biggest bang for the buck improvement by far. Changing anything more than that could improve things a little more, but I don't think it would be enough to be able to tell a difference.

    Have a good one, Jeremy
     
  5. jeremy v

    jeremy v Guru Class Expert

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    Eyebeatbadgers,

    Mag drive type pumps, canisters, and powerheads that have the pump housing that allows the impeller to spin either direction in order to create flow can never really create enough intake vacuum to cause cavitation. You really need to get into the true centrifugal pumps that have a housing and impeller design just like an automotive turbocharger before the design is efficient enough to cause that issue. Even then, you also need to have a higher head style pump before the issue can become significant enough to start causing any actual pump damage.

    In relation to supersaturated oxygen levels that can occur in aquariums from vigorous plant growth during the day. Pretty much anything that forces water around can pull that extra oxygen out of solution and form bubbles or mist in the tank. Even though that is technically cavitation if a pump is doing it, pump intake design and/or starvation are not causing it, and that created gas will never be enough to damage anything.

    Gerry is right, you are just pulling unfiltered tank water through your CO2 needle pump, but there is nothing inherently wrong with that. Your filtration ability will just remain exactly what it was before you added the needle pump, but the needle pump is increasing the total system flow and adding more circulation to the tank. You basically just did the equivalent of adding a powerhead to the tank to add circulation and diffuse CO2, but you mounted it in a way such that the powerhead doesn't actually have to sit in the aquarium.

    I think you would gain a noticeable flow increase out of both your needle pump and your canister filter by increasing the intake pipe size from the tank to the "T" where the needle valve and canister intake lines split from each other. Just going up one pipe size should be fine. That will be your biggest bang for the buck improvement by far. Changing anything more than that could improve things a little more, but I don't think it would be enough to be able to tell a difference.

    Have a good one, Jeremy
     
  6. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    Very informative, thanks so much!
     
  7. Tom Barr

    Tom Barr Founder
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    For such a low flow system using the Rena, use something like this:

    Aqua medic reducing tee - Google Product Search

    You can modify the inlet and make it even a smaller hole so that smaller bubbles come through.

    This has no impact of flow rates and can be placed right after the Rena and with 2-4ft of return hose, gets pretty dissolved by the time it enters the tank.

    You can also make your own or modify the tee so that you can add a small airstone inside the Tee itself, or even a small diffuser disc if you wanted.........

    Simply connect the stone to some airline inside the inlet of the Tee.

    Then let the stone just wiggle in the current inside the tubing. You can make a large PVC, say 1" or 1.5, or 2" section for this to accommodate the large stones or diffuser disc.

    Cal Aqua Labs did something like this made out of glass but is fragile and hard to clean and can only handle 160 GPH/300gph.

    Do not break them or knock them too hard!!!

    CAL AQUA LABS - Inline diffusers

    Regards,
    Tom Barr
     
  8. Panda

    Panda Guru Class Expert

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    good to know
     
  9. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    I am introducing the CO2 gas into the system similarly to the first item you mentioned, but instead of buying a 10 dollar chunk of plastic, I drilled a small hole in the tubing, and used some pliers to pull the CO2 tubing through. I then covered the area with some E6000 craft glue, which you've recommended before I believe. If that won't seal, I'll be shelling out some $$ for the proper part, thanks for that link! I didn't know such a thing existed, never thought to google it :eek:

    The glass inline diffuser is neat, but pricey, and I like the extra flow the needle wheel pump gives. The needle wheel pumps are ideal for small setups like mine, but rather ugly to look at every day. I think this setup is going to be ideal for me. Everything will be cured and ready to go tomorrow, and I'll post a conclusion in a day or two.
     
  10. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    The reality of things

    While the setup I posted earlier was a nice idea, and I'd seen several others recommend it, it simply will not work. Here's why:

    [​IMG]

    Why would the water want to go all the way up to the tank, when it can just flow backwards through the pump and back through the filter again? A one way "check valve" sort of part would be needed to keep that from happening, but I doubt that the needle wheel pumps like mine would be able to overcome such a thing.

    I also tried moving the output side "T" as high as possible, to make the filtered water go through the spray bar, but that was a bad idea :eek: My mind does not always think logically.

    So, after thinking, tweaking, and spilling gallons of water when the faceplate of the pump twisted off, I decided to just run the pump inline with the canister, after the reactor, and all is well. I get enough flow throughout the tank, and the bubble size and quantity is ideal, actually more uniform throughout the tank than before.
     
  11. VaughnH

    VaughnH Lifetime Charter Member
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    I'm surprised that the schematic shown above didn't work. The pressures in the hoses below the tank should all be very nearly equal, equal to the head of water above that point. So, there should be no pressure difference to drive the flow backward through the needle wheel pump. That needle wheel pump will produce a small head pressure itself, which also acts to resist back flow through it. This is assuming that the system was thoroughly bled, so no air bubbles were present anywhere in the system. (If the filter output in the tank is restricted with a spraybar or any type of nozzle that accelerates the flow from the nozzle, it won't work, because that does cause a pressure difference across the needle wheel pump.)
     
  12. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    I tried the first setup with and without a spraybar, and no difference either way. Here's a picture I took with spraybar highlighting the amount of flow I was, er, wasn't getting.:

    [​IMG]
     
  13. SeanS

    SeanS Junior Poster

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    Eyebeatbadgers,

    I do appreciate you going through the mistakes and flooding of fine tuning this method, so the rest of us might not have to;)

    A couple questions for you:
    Were all the proper fitting to run the gen-X inline included with the pump?
    I found an old version of one of these at the store I work at, and it did not include enough hose barbs, nor did any or them appear to be the 5/8 line the Renas use.
    I don't now where I could find these barbs with the appropriate threading...

    Do you find that the pump boosts the filter output to a significant extent?
    Anything that could boost the output of a Rena would be a nice improvement:)

    How small is the bubble size? Would you consider them to be microbubbles, or a smokelike mist?

    Thanks.
    -Sean
     
  14. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    The proper fittings were not included with the pump. I bought two from Ace Hardware that were 5/8" barbs to 1/2" MPT threads. The only problem with the barbs that you'll find anywhere, is that the threaded portion of the barb is not long enough to make good contact with the pump's threads, since they are recessed so far back in the pump. I was able to get them leak free on the second try, with a lot of plumber's tape. I do not know how long that will last though. You may want to look into the Octopus brand pumps to see what their threading is like.

    The pump certainly does boost the flow a decent bit. The entire tank gets mixed well with the spraybar attachment, whereas before there were several dead spots, due to the big stump I have in my tank. The other good news is, I turn the pump off with the lights and CO2 and night, and there is still stock-like flow through the spraybar.

    The Co2 is microbubbles, not a smoke. The smoke-like mist is only going to come with a mazzei, but this setup only costs about 20 bucks for the pump, whereas the mazzei setup will cost 200+ for a high performance pump plus the mazzei part and PVC parts. The bubbles are smaller now that the pump is inline though, much less distracting than before when the pump was located in the tank.

    Another important point is that the Gen-X pump is dead quiet out of water. I screwed it directly to the wood of the stand, and you cannot hear it over the hum of the Rena, which is minimal in itself. The pump was loud for about a day or two, I guess it had some air in it.

    Overall I'm still very satisfied with this setup, my tank looks better without the crap in it, and my plants are looking healthy.

    One final thing, before you spend money and undertake any project, make sure you're taking advice from someone who has actually done it. Lots of folks on the net just spew up information that they read from someone else, and that person just heard it from someone else, etc., etc. I had several people tell me that the first setup I was going to use would work fine :rolleyes:
     
  15. jeremy v

    jeremy v Guru Class Expert

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    Eyebeatbadgers,

    I can see how you were frustrated by the advice given to you not working, but you omitted an important fact in your original question that directly led to all of this. Your original question was not asking if the setup would even work, it was asking what you can do to get better flow through it with less restriction. If your question is about the optimization of your setup, all of us have to naturally assume (and give advice based on that assumption) that you have actually turned the setup on and that it works to begin with, otherwise why would you be asking how to optimize it?

    95% of all possible setups that are like the one you were asking about would have worked exactly how we were implying, and it would have worked much better and with higher flow rates and greater efficiency then you have now with your current setup. Many people on this forum and others are running setups just like the one we were suggesting for you very successfully. We might have mentioned to you that your setup could be one of the 5% that wouldn't work (because your needle pump is one of the few that is too weak to overcome the slight head pressure of the canister output line) if we had actually known that you hadn't tried it yet.

    The reason I felt compelled to respond to your comment, is because I have learned a lot from this forum about algae control, fertilization, circulation, and how to grow plants successfully. I think it is one of the best forums out there related to planted tanks and aquarium filtration systems, and it has one of the lowest ratios of bad advice to good advice of any forum I have ever visited. I value the opinions of everyone on here, and I find it very offensive to myself and the other people on here that did try to help you to be treated in return as you have treated us. The people that tried to help you didn't need to voluntarily spend their time to help you find an answer to your question, but they did. We all have the same goal of wanting you to have the best setup possible.

    Have a good one, Jeremy


    P.S.- The second you think you have all the answers is the second that you actually have none, and it is also the second you stop learning. True wisdom actually humbles you and fills you with even more questions and a deeper respect for the similarities and differences in other people and what they know. Wisdom also helps you to realize that there is much more to every problem than is always understood or realized at first glance.

    Remember, a truly wise person that understands a particular issue from many different angles (and all of the factors involved) can't be led astray no matter what advice is given, because he can see the truth from the lies from the very beginning.
     
  16. jeremy v

    jeremy v Guru Class Expert

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    Eyebeatbadgers,

    I can see how you were frustrated by your plumbing issues and how it can seem like you got bad advice, but I don’t think you got bad advice at all, just advice that didn’t quite match with your exact unlikely situation. That happens sometimes. Your original question was not asking if the setup would even work, it was asking what you can do to get better flow through it with less restriction. If your question is about the optimization of your setup, all of us have to naturally assume (and give advice based on that assumption) that you have actually turned the setup on and that it works to begin with, otherwise why would you be asking how to optimize it?

    95% of all possible setups that are like the one you were asking about would have worked exactly how the advice given to you implied it would, and it would have worked much better and with higher flow rates and greater efficiency then you have now with your current setup. We might have mentioned to you that your setup could be one of the 5% that wouldn't work (because your needle pump is one of the few that is too weak to overcome the slight head pressure of the canister output line) if we had actually known that you hadn't tried it yet.

    The reason I felt compelled to respond to your comment, is because I have learned a lot from this forum about algae control, fertilization, circulation, and how to grow plants successfully. I think it is one of the best forums there are related to planted tanks and aquarium filtration systems, and it has one of the lowest ratios of bad advice to good advice of any forum I have ever visited. The people that tried to help you didn't need to voluntarily spend their time to help you find an answer to your question, but they did. I think I can speak for all of us in saying that we all have the same goal of wanting you to have the best setup possible.

    Have a good one, Jeremy


    P.S.- Remember, a truly wise person that understands a particular issue from many different angles (and all of the factors involved) can't be led astray no matter what advice is given.
     
  17. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    My original intention when I started this thread was to find out if this type of setup would work or damage my filter. Reading back, I suppose I didn't make that crystal clear. When I'd asked other people, I heard either it will work fine, or "No!! That pump will cavitate your canister and start a fire!!" :) Since I have no real knowledge of fluid dynamics, or how these pumps really work in the first place, I assumed such a setup would work fine. I now have it set up, and working beautifully, so at least there is a happy ending.

    Maybe you or someone here could tell me, if I had a higher output Gen-X model pump, would my first situation have worked? I assume from my findings when I was tinkering around with it that the 1000 liter per hour model is just too puny to push any amount of water resistance. Would a faster spinning impeller (I assume that's the difference in output levels) be able to overcome the canister's pressure? I know now that you could never turn the auxiliary pump off in that type of setup, as the canister will always want to flow backwards through the pump, no matter what the size or brand, as long as it is the same style pump as I'm using. I do not know if a pump like the guys fiddling with mazzei style injection would allow backwards flow. Of course if I had one of those type of high output pumps, I wouldn't be dinking around with needle wheel diffusion

    I didn't mean to convey that I got any bad information here, the first post you made in this thread helped more than all the research I'd done in the past few weeks! Other forums that I'll leave unnamed are the problem. When I want to help people get fertilizer routines down, or help newbies with Co2, I'll post there. When it's time to learn, or if I have a unusual question, I always come here first.

    I wish I had the funds to test several different pumps, but alas, I'm a poor student. Maybe someday:cool:
     
  18. jeremy v

    jeremy v Guru Class Expert

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    Eyebeatbadgers,

    I can’t answer your question with certainty related to a higher output Gen-X pump, because I couldn’t find any pump output curves for them online. It is hard to find that stuff for smaller pumps of any brand. They usually do at least tell you the maximum head capacity, but I couldn’t find that either after searching for a few minutes.

    The issue is that a larger needle pump might be able to flow more water when you are using it in a circulation-only type of setup (like with a powerhead in the aquarium), but still not be able to flow that increased water volume against any more head resistance than your smaller pump can, so you might still have the exact same issue with the pump backflowing. I would say that it is actually probable now that the first pump of the same brand didn’t work. With most smaller pumps, all that really changes as the pump capacities go up is the size of all of the parts, so the weak pressure capability of the smaller pump will most likely still be there with the bigger one.

    With the setup you have now, the canister is having to push its’ output water through the needle wheel pump when the needle wheel is off at night, which probably does cut the canister’s output flow a little bit. You could eliminate this by experimenting with a setup where you take the exact same plumbing setup you have now, and you just add a short second canister output line that T’s off the existing canister output line right before the needle pump, bypasses the needle pump, and then T’s right back into the existing canister output line just after the needle pump.

    With that setup, there would be no pressure difference between the intake and output of the needle wheel itself at any time, both pumps will still share the same plumbing into and out of the aquarium, and since the needle wheel is on a secondary parallel leg of the canister output it won’t restrict the canister’s flow at all when the needle pump is on or off.

    That would be something worth trying, and based on your pictures it looks like you already have all the parts you need to try it. Worst case scenario would be that the total flow out of your spraybar goes back to what it was when it was just the canister filter during the day, and at night your flow is increased a little from the canister not needing to pump water through the stopped needle pump.

    You might however find a worthwhile benefit that would be caused by a weird interaction with the flows through the canister output line and needle wheel line when both pumps are running. The interaction would seem very counter intuitive, but it would very likely actually help chop up and dissolve your CO2 more fully so you would have less micro-bubbles of CO2 in the tank. I am not going to tell you what would happen or why though. If you do find there are less CO2 bubbles in the tank, you can learn a lot by trying to figure out why.

    A clue to what might happen can be found by watching the CO2 mist in the lines. If you can see through the pipes when it is all up and running, look at the water in the lines and see if you notice anything strange about the direction some of the CO2 bubbles are traveling. Another clue is that it will only happen if your canister is flowing less total water then your needle wheel is pumping. If everything looks/flows just how you would expect, that just means that your canister has a higher flow capacity than the needle pump with your particular setup.

    Have a good one, Jeremy
     
  19. SeanS

    SeanS Junior Poster

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    Thanks. I think I am going to steal your setup for my own tank. It seems to be a great solution for those of us who have tanks too small for a venturi.
     
  20. eyebeatbadgers

    eyebeatbadgers Junior Poster

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    That's a good idea Jeremy, I hadn't thought of bypassing the pump in that manner. The needle wheel pump really doesn't affect the output of the canister in a measurable way when it is off, so I probably won't do any more tubing cutting any time soon. I did find the head rating for my pump, and I believe the max head rating was six feet, but had considerable flow loss.
     
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