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