On Sun, 05 Sep 2004 10:01:22 -0600, W Dale
wrote:

===Any one have recommendations for good external pump for a 4,000+gal.
===pond? I am trying to get ready for the eventual demise of my two SG
===4300's. What I keep reading is that for larger ponds, external pumps
===are the way to go.
===Thanks for your comments and input
===W. Dale


Most effieciency in the external pumps come from their size and the
amount of windings they have, as comparted to submersibles. While some
sub types run in oil, and others are encapsulated n epoxy, they still
build up heat and heat in any electrical device is wasted energy, as
the hotter it gets the more it looses. Subs get warm even submerged in
water. Open air designs as most externals are are pretty good at
getting rid of heat and not transferring latent heat to water in the
process.

I think the whole concept of sub is great from the average homeowners
standpoint with ease of installation and wiring.......Usually just
slip on tube and plug it in after dropping it in the pond. Ext types
usually are a lot more involved and not geared to as many home owners
abilities or uses, in size and complexity. Ext also operate more
efficeintly mainly due to the usual type of plumbing they are hooked
up with. Lots opf things will govern just how efficient any pump is.

There was just a 3 month old Hayward Super Pump of 1/2 hp (420 watt)
ext pump sold on ebay for $61.00 complete with primer and filter
basket strainer. That pump lists for close to $300.......and puts out
54 GPM at 20 foot head or 29 gal a minute at 40 feet of head which is
pretty darn good. I had my eye on it but did not get to the computer
in time to place my bid this morning......

I am currently looking at AZponds pump and strainer basket pumps that
they have on sale. A lot of the inground pool type pumps will work
more than satisfactorily for pond use, and since there are a lot of
pools / hot tubs out there as compared to ponds I find the prices on
them a lot lower than the average typical water garden pumps cost.

One thing to be aware of though is a lot of companies "UP" rate their
pumps to make it sound better. For example. A pump rated at say a
service factor of 1 and of 1 hp . Well if you use a service factor of
1.5 for that same pump / moptor you now get a pump rated at, 1 1/2 hp.
It will not pump any more than the 1 hp pump will as its the same
exact pump and motor combination, but has a different service factor,
but odds are running at that higher service factor it will not last as
long as the same exact pump rated lower..........its all a numbers
game. Lower service factor the better.......so why pay more for a pump
with a different label on it with a claimed higher hp. Thats about
all thats really changed is the labels on a lot of pumps.......You are
lead to believe if you get a 1 1/2 hp it won;t have to work as hard as
a 1 hp and its only $20 bucks more, but for your 20 bucks all you got
was a new label and a pump with a shorter overall lifespan. Its a
given so many watts equal a horsepower. What that wattage is slips my
mind at the present.
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