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Re: NFC: Sweeping Powerheads (was Pressure... under pressure... )

I've gotta agree with Wally here.  They get gummed up, and need constant
attention to clean them up.  The pivots have never worn out for me -- they
just get gummed up.  A cleaning fixes them... for all of a day or two. :)

Joshua.
----- Original Message -----
From: Wally Billingham <wallybillingham at wallybillingham_com>
To: <nfc at actwin_com>
Sent: Thursday, February 28, 2002 12:33 PM
Subject: Re: NFC: Pressure (prolly off-topic. :)


> "I was intrigued to see a powerhead at my LFS a couple of weeks ago that
has
> a rotating output, so that it changes direction almost like a sprinkler
...
> that could be a neat kind of thing to do in some set-ups."
>
> Hi Doug,
> I thought they were cool too, until I got one. The idea is awesome but if
> you are talking about the "Power Sweep" ones they are JUNK! The design is
> poor and after a few months the pivot point wears out and they stop
turning.
> Everyone I know who has tried them has had the same problem. I wish
someone
> could make one that did the sweeping that would last.
>
> Wally
> ----- Original Message -----
> From: Doug Dame <dameda at shands_ufl.edu>
> To: <nfc at actwin_com>
> Sent: Thursday, February 28, 2002 12:18 PM
> Subject: Re: NFC: Pressure (prolly off-topic. :)
>
>
> >
> > While it might seem like this system is not necessarily optimally
> engineered, note that if the UV is going to be effective in doing its job,
> "dwell time" and proximity of the water passing by are critical concerns,
> and that argues powerfully against an extremely high rate of flow.
However,
> the desired overall turnover rate for the tank water and the desired
amount
> of current in the tank (to keep the occupants happy) are also obviously
> concerns and part of the possible trade-offs involved.
> >
> > One book that quantitatively addresses these kinds of calculations re
the
> UV filter ... and also provides formulas for estimating the total amount
of
> head pressure lost due to bends and turns in various kinds of plumbing ...
> is
> >    - Aquatic Systems Engineering : Devices and How They Function
> >    -    by Pedro Ramon Escobal, Martin A., Jr. Moe
> >
> > You might want to look into that before changing all your piping.
> (Consult your favorite vendors of fish books.)
> >
> > Also of course if you just want more current flow in the tank, you could
> simply add a $25 powerhead that was unconnected to the existing filtration
> plumbing.
> >
> > HTH
> >
> > Doug Dame
> > Interlachen FL
> >
> >
> >
> >
> > >>> JLW at dune_net Wednesday, February 27, 2002 9:10:36 PM >>>
> > Hey all.
> >
> > I've got a 92G Corner tank, with an overflow system.  I've got a massive
> > pump on it, which, at the output end, just doesn't seem to give much
flow.
> > It is rated at 2400 GPH.  I'd guess it is putting out less than 100 GPH.
> > The impeller is clean, etc. etc.  The trouble is... the way the former
> owner
> > set this tank up, the pump comes immediately after a sump, and then must
> > push water thru a Rainbow LifeGuard MechaniFilter, and a UV Steriliser.
> > Worse, it pumps up about 4", then back, then drops down, thru the
> > mechanifilter, up again (8"), left to the UV, up the UV (18"), right out
> of
> > the UV, and finally up the tank again.  All these bends, turns, rises
and
> > falls are eating up my head pressure, and thus dropping my flow to next
to
> > nil.
> > Now, my question is this:  If I move the pump to directly under the
tank,
> so
> > the bends, rises, falls, etc. are all before the pump (and, thus, more
or
> > less powered by the natural flow of water, I think?) would this give me
> > increased flow?  Obviously, when I rework this in a few days, I'm going
to
> > try to minimise the twists, turns, rises, and falls, but ... I'm
wondering
> > where the best place to put the pump is.
> >
> > Joshua.
> >
References: