In a recent posting here, someone had lost their pump, and was wondering
what needed to be done to keep their fish safe until a replacement could
be found/installed. That got me thinking (never a good thing, but I
digress) a bit about how to minimize the short-term impact of a pump
failure. Going under the assumption that it takes a certain amount of
power to pump a given quantity of water, would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump? It shouldn't
take any more power to pump the water; the only additional cost would
be the initial plumbing and pump costs. It might be a worthwhile
tradeoff for peace-of-mind to put out a little more money upfront to
make sure that a pump failure won't take down a whole pond ecosystem.

Comments?

Scott

Not much of a comment, except to say:

Oh, man, how my father would have loved newsgroups with questions like this,
sigh...... He was an engineer, we had a house on Lake Erie, and a cottage
on Georgian Bay........ he used to get the monthly(?) reports from the Army
Corps of Engineers about water levels on the Great Lakes. And, I swear,
only my dad could get excited when he talked about "acre feet" (the amount
of water necessary to cover one acre with one foot of water).

Through in a question about pumps in parallel, and he would have been in his
element, sliderule & all!

[I realize this post was of no help whatsoever to Scott, who asked the
question, but the memories that the question evoked are priceless.]

And then's the question that occurred to me when I read an earlier thread
(very embarrassing not to know the answer, as I'm sure I should know it):
"Does a pump have to work harder to move water that's 6 feet under the
surface than water that's 2 feet under the surface"?

Anne Lurie
Raleigh, NC







"Scott Evans" wrote in message
...
In a recent posting here, someone had lost their pump, and was wondering
what needed to be done to keep their fish safe until a replacement could
be found/installed. That got me thinking (never a good thing, but I
digress) a bit about how to minimize the short-term impact of a pump
failure. Going under the assumption that it takes a certain amount of
power to pump a given quantity of water, would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump? It shouldn't
take any more power to pump the water; the only additional cost would
be the initial plumbing and pump costs. It might be a worthwhile
tradeoff for peace-of-mind to put out a little more money upfront to
make sure that a pump failure won't take down a whole pond ecosystem.

Comments?

Scott

Scott Evans wrote:

would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump?


I think that might be over complicated. I solved the problem by having my
main pump and a back up of about the same oomph. The difference is that my
main pump is a) more expensive because b) it is way more energy efficient.
My back up is just cheap because it only has to work long enough to repair
my main pump.

Joe



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Anne Lurie wrote:

"Does a pump have to work harder to move water that's 6 feet under the
surface than water that's 2 feet under the surface"?

Nope. Head is from the surface.


Joe



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Scott,

The redundancy of parallel pumps is good design, and if you are trying to
move certain amounts of water, it is cheaper on the electric bill as well.
If you want to move 8000 gallons per hour with a Sequence pump, you have to
step up to the high head, read as high energy consuming pumps, whereas you
can get by with two smaller low head pumps using much less energy. If one
goes out, you still have half the flow through the filter, and over the
waterfall. Aquadyne filters say it is better to have two filters with two
pumps than to have only one large system.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"Scott Evans" wrote in message
...
In a recent posting here, someone had lost their pump, and was wondering
what needed to be done to keep their fish safe until a replacement could
be found/installed. That got me thinking (never a good thing, but I
digress) a bit about how to minimize the short-term impact of a pump
failure. Going under the assumption that it takes a certain amount of
power to pump a given quantity of water, would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump? It shouldn't
take any more power to pump the water; the only additional cost would
be the initial plumbing and pump costs. It might be a worthwhile
tradeoff for peace-of-mind to put out a little more money upfront to
make sure that a pump failure won't take down a whole pond ecosystem.

Comments?

Scott

In article , "Anne Lurie"
writes:


Through in a question about pumps in parallel, and he would have been in his
element, sliderule & all!

sounds like my dad - sliderule and all, a mechanical engineer figuring things
out til the day he died.

Karen
Zone 5
Ashland, OH
http://hometown.aol.com/kmam1/MyPond/MyPond.html
My Art Studio at
http://members.aol.com/kmmstudios/K....M.Studios.html
for email remove the extra extention

There is a school of thought referred to as R.A.I.P., or Redundant Arrays of
Inexpensive Pumps. RTB explained it nicely above; Joe also has a very good
idea. Many of us start off with pumps that were easily "findable", like the
Little Giants or Beckett pumps. But these are inefficient
operating-cost-wise. It's a good idea to do as Joe suggests: replace it
with an efficient pump, and place the other in storage as a back-up. It's
also nice to have another pump to run a quarantine or hospital tank . . .

Lee

"Scott Evans" wrote in message
...
In a recent posting here, someone had lost their pump, and was wondering
what needed to be done to keep their fish safe until a replacement could
be found/installed. That got me thinking (never a good thing, but I
digress) a bit about how to minimize the short-term impact of a pump
failure. Going under the assumption that it takes a certain amount of
power to pump a given quantity of water, would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump? It shouldn't
take any more power to pump the water; the only additional cost would
be the initial plumbing and pump costs. It might be a worthwhile
tradeoff for peace-of-mind to put out a little more money upfront to
make sure that a pump failure won't take down a whole pond ecosystem.

Comments?

Scott

Scott Evans wrote:

would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump?

I like it. Even having the second pump off but plumbed in and ready to
take over would be nice. Bonus points for automatic switchover...

I am of the opinion that one large, properly designed pump would cost
less to purchase and operate than several smaller pumps, particularly
when you consider the flow losses due to the plumbing associated with
multiple pumps (either each pump must have it's own filter, or each
pump must have a check valve to prevent backflow in the event it
fails).

I would take another approach. One of the 'authorities' tried an
experiment using an inexpensive aquarium air pump and an air stone.
He decided to see if this would provide sufficient oxygen for his koi
in the event the main pump shut down. It also had the advantage it
could be run off a car battery and inverter in the event of a power
outage. Total cost was under $15 for the pump and air stone.

He described hooking the thing up one evening, turning the main pump
off, then checking the pond every hour. Unfortunately he fell asleep,
only waking up after the main pump had been off more than 8 hours.
He was rather relieved to find all his koi were still doing well, with
no signs of any shortage of oxygen. Based on his report, this
approach should allow you to keep your koi healthy for an extended
period in the event of a main pump failure or power failure.

PlainBill

On 26 Aug 2003 21:36:28 GMT, (Scott Evans) wrote:

In a recent posting here, someone had lost their pump, and was wondering
what needed to be done to keep their fish safe until a replacement could
be found/installed. That got me thinking (never a good thing, but I
digress) a bit about how to minimize the short-term impact of a pump
failure. Going under the assumption that it takes a certain amount of
power to pump a given quantity of water, would it make more sense to
have multiple smaller pumps hooked up in parallel (with appropriate
back-flow check valves) rather than a single large pump? It shouldn't
take any more power to pump the water; the only additional cost would
be the initial plumbing and pump costs. It might be a worthwhile
tradeoff for peace-of-mind to put out a little more money upfront to
make sure that a pump failure won't take down a whole pond ecosystem.

Comments?

Scott

PlainBill writes:

I am of the opinion that one large, properly designed pump would cost
less to purchase and operate than several smaller pumps,

Could be.

particularly
when you consider the flow losses due to the plumbing associated with
multiple pumps (either each pump must have it's own filter, or each
pump must have a check valve to prevent backflow in the event it
fails).

You can make the flow losses identical by adjusting pipe sizes so I
don't think it's a factor.

He described hooking the thing up one evening, turning the main pump
off, then checking the pond every hour. Unfortunately he fell asleep,
only waking up after the main pump had been off more than 8 hours.
He was rather relieved to find all his koi were still doing well, with
no signs of any shortage of oxygen.

Its encouraging. He proved that it works for 8 hours for his
fish load, pond volume, temperature and initial oxygen level.

have really good aeration. dont feed the fish and they will be fine until you can
replace the pump. just keep an eye out for ammonia, dump in amquel if it does show
up. aeration is much more important than filtration. I have two big air pumps.
Ingrid

(Scott Evans) wrote:
how to minimize the short-term impact of a pump
failure.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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http://puregold.aquaria.net/
www.drsolo.com
Solve the problem, dont waste energy finding who's to blame
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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