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Really bad idea?

Discussion in 'General Discussion' started by phishcrazee, Jun 11, 2009.

  1. phishcrazee Experienced Reefkeeper

    Riverside
    Ratings:
    +0 / 0 / -0
    So the return pump on my 75g is going.......it's a mag 7 I believe.  I have a mag 18 that I could swap out with the old pump, but my HOB overflow is only rated for something like 600 gph.  Will I flood my tank?  How can I cut back on the mag 18's power (besides putting it down in the basement, lol)?  I don't really want to buy another pump, as we'll soon be moving everything to a bigger tank.
     
  2. CyberJester

    CyberJester Inactive User

    655
    Ratings:
    +0 / 0 / -0
    If you can connect a valve on the output of the pump, this will allow you to control the amount entering your tank.  You can adjust until the you hit the threashold amount.
     
  3. Eric Experienced Reefkeeper

    West Des Moines, IA
    Ratings:
    +33 / 0 / -0
    Fawn,
    Put a valve on the return from the Mag...never mind, got beat to the answer.
    You can also undersize the return to take some of the load away from the valve.  For instance, using a return of 1" would yield approx. 976 gph whereas .75" would give you a return of 757 gph, obviously .5" would restrict further.  Used a guesstimate on your tank of 5' return with 5 rt angles.
    Still a lot of pump!
    -Eric
     
  4. REEFer Madness

    REEFer Madness Inactive User

    867
    Ratings:
    +0 / 0 / -0
    I think with going to a pump that big, Fawn you'll need to "T" a section in your pump. I don't think you'll be able to close a valve enough with that much flow.  I put a Mag 12 on my 72 and it was too much with 1 HOB overflow with just a single line going into my tank.  In fact, I bought a second HOB and both couldn't handle it without making me feel comfortable.  So I did like what I sketched out. 
    About 8 inches above your pump, put in a T and run that anywhere in your sump and put a valve at the end of it also. So you will have one valve each exit. Then play around with the valves until you're comfortable with how much is going into your tank.
    Sorry for the crude illustration, but I don't have any of the fancy stuff like microsoft paint even.
    X is place to put ball valves.
                        Return
                            l
                            l
                            l
                            X
                            l
                            l
                            l
                            l
                            l
         _X ________l   
     
  5. phishcrazee Experienced Reefkeeper

    Riverside
    Ratings:
    +0 / 0 / -0
    Ok, thanks guys! Looks like I have some plumbing to do :)
     
  6. Bela

    Bela Inactive User

    Ratings:
    +0 / 0 / -0
    I would do what reefer madness suggested. This way you are not putting unneeded strain onto the pump :)
     
  7. got2lb Well-Known ReefKeeper

    540
    Clarksville, IA
    Ratings:
    +19 / 0 / -0
    I had mine setup like reefer madness was saying you can kind of see it in the picture. The main line is going straight up out of the pump with a ball valve on it and then it tee's back into the sump with another ball valve.

    [​IMG]
     
  8. phishcrazee Experienced Reefkeeper

    Riverside
    Ratings:
    +0 / 0 / -0
    Need to go to Menards now..........I'm going to try Reefer Madnesses/Got2lb idea :)
     
  9. Eric Experienced Reefkeeper

    West Des Moines, IA
    Ratings:
    +33 / 0 / -0
    Posted By Bela on 06/12/2009 09:23 AM
    I would do what reefer madness suggested. This way you are not putting unneeded strain onto the pump :)
    I don't believe that it would put undue strain on the pump - it's an impeller spinning in water.  Mag 18 shuts off @ 21' as the weight/pressure from the water is too much for the pump to overcome, therefore if I ran a 21' vertical lift I would destroy the pump?  And why wouldn't you undersize the return?  The output for the Mag 18 is only 3/4"?  A 3/4" return with some extra elbows would effectively reduce the output without worrying about a valve.  If a 3/4" return caused "unneeded stress" on the pump then it would either destroy itself or dramatically reduce the useful life and Danner would have used something different.
    Let's face it, even with a "T" and two valves, this is too much pump for the application unless as a band-aid for a short time (which it sounds like it is) as they'll be several hundred gallons per hour dumping back into the sump.
    [​IMG]
    -Eric
     
  10. xroads Veteran Reefkeeper Vendor

    La Porte City, IA
    Ratings:
    +1,014 / 6 / -0
    Another option you can do it to use some lockline on the return. Split into 2 or 3 returns with some lockline & nozzles on that. It will restrict the flow somewhat & help you increase the flow pattern within the tank eliminating dead spots.

    I would then put a valve on the return & then adjust it to where you need.

    I dont think you need the t return either
     
  11. Bela

    Bela Inactive User

    Ratings:
    +0 / 0 / -0
    I am only going from what I had read about putting more strain on the pump than is necessary. Perhaps I don't really understand how pumps work but, to me, it stands to reason that the more work the pump is doing, generally the shorter the expected lifespan of that pump can be expected to be? Again, I am new to this so maybe I am incorrect in these assumptions?
     

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