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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.

----- 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 ...
>    - 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
> 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
> 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
> 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,
> 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.

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