| When
replacing a fountain pump or choosing a new ones, first there are
some keys terms to keep in mind:
"Head"
: This is the maximum vertical lift of the pump.
For example, a 6' head means the pump is rated to pump water up to 6 feet high.
Note, however, that at 6 feet the pump would be providing very little
water, a gallons per hour around zero. So if you need to pump, say,
200 ph at 72”, you will probably need about a 500-600 gallon per
hour pump to do the job. See a "pump curve" for the amount
of water pumped to various heights.
"GPH" :
Gallons per hour, usually rated at different heights
"GPM" :
Gallons per minute, usually rated at different heights
"Pump
Curve" : The amount of water volume "curved"
according to various heights. A 500 gallon per hour pump, for instance,
might pump 500 gallons per hour at 0” lift, 350 gallons per hour
at 24” of lift, and so forth.
"Water
Volume" : This is controlled by a few factors. One factor
is the size of the pump, as covered above. How wide should your
tubing be? Tubing is measured in two ways: inside diameter (i.d.)
and outside diameter (o.d.). Very thin i.d. tubing will greatly
reduce water flow. Many customers are shocked when they find that,
after hooking up their 500 gallon per hour pump to ½” inside diameter
tubing, they are only getting what they consider a trickle. Well,
about the most they will get is 200 gallons per hour or so. They
have restricted the flow too much. When purchasing a pump, find
out what size of tubing is supposed to go with it. Another problem
is running the tubing too far. Long lengths of tubing create resistance.
If your pump calls for ½” i.d. tubing, for instance, but you are
running the tubing twenty feet from the pump, it is a good idea
to use ¾” tubing instead so as not to cut down too much on flow.
How much water
do I need? What size of pump?
This question
is answered in part
by whether you want a “trickle” or a roar. For fountains, you will
usually find a recommended flow. For waterfalls, use this as a rule
of thumb: for every inch of stream width or waterfall "sheet,"
you will need to deliver 100 gallons per hour at the height you're
pumping. So if you are building a 12” wide waterfall that is three
feet tall, you need to buy a pump that will be pumping 1200 gallons
per hour at three feet of height.
For ponds, whenever
possible, it is a good idea to re-circulate the water once an hour,
more often if possible. Thus, if your pond is 500 gallons, try to
buy a pump that will re-circulate water at a rate of 500 gallons
per hour. For really large ponds, this is not necessary and is far
too expensive.
For a nice waterfall
effect, we usually advise about 4000 gallons per hour or more at
the top of the waterfall. This creates enough volume for a wide,
crashing spill. Adjust stones to soften the splash if desired.
When Is an
External Pump Appropriate?
“In-line” pumps
provide the "most bang for the buck" in two ways. For
one, the purchase price is quite reasonable for the high volume
of water being pumped. But even more importantly, these pumps dramatically
outperform typical submersible pumps, cutting electrical costs two
to three times. Since electrical costs for a pond can easily run
from thirty to one hundred dollars a month, choosing the most energy-efficient
pump is tremendously important.
However, if you
need a lot of "head," that is, if you are pumping to a
height of more than say, seven or eight feet, or if you must pull
the water (not "push", for in-line pumps push water fine
but don’t pull well) a long distance from the pond to a skimmer
located far away, then these pumps probably won't work for you.
How About
Battery-Operated Fountain Pumps?
We receive many,
many calls about battery-operated pumps. While there are companies
who manufacture pumps that can operate on "A" and "AA"
batteries, we have not found a battery-operated pump that lasts
or that is reasonably priced. For those customers who need battery
fountains for wedding centerpieces (a common request), we suggest
finding the one you want and buying as many as possible at a store
like Wal-Mart. You get the whole fountain for as good of a price
as we could get you these specialized pumps all by themselves!
Where is the
Pump Made?
Pumps, like anything
else, are made all over the world, and we suggest you buy pumps
from someone who will stand by a guarantee and who has testing programs
before marketing their pumps. It used to be that Asian pumps were
quite bad but this is changing. What matters most is how well the
pumps have been engineered and the materials used in the production.
Italy for quite a while has been the major manufacturer of
fountain
pumps (think of how long Italians have had fountains), but Germany,
Korea, Taiwan, and China are making pumps as well. Most American
fountain pump companies (for example, Cal Pumps and Beckett) have
their pumps manufactured overseas. As long as American engineering
is used and the plans are followed, this should not be a problem.
Should my
Pump Have a 2-wire plug or a 3-wire plug?
Outdoor pumps
should always use a grounded, 3-wire plug. Indoor fountains sometimes
have 2-wire and sometimes 3-wire plugs. For people wanting a really
thin cord, 2-wire pumps provide the more aesthetic experience. Some
retail stores require a 3-wire pumps even for indoor fountains (though,
ironically, they might not for aquarium pumps), and these thicker
cords can be hidden by plants, stones, or other decorations. All
pumps must be connected to a GFI outlet for safety.
Why do pumps
burn out so often?
95% of the
time the customer has let the pumps get hot by running them dry.
Most fountain pumps are water-cooled and once the fountain is dry
they burn up. Usually there is nothing you can do about this other
than to buy a new pump. Also, however, pumps are supposed to be
cleaned every so often by opening up the impeller case on the fountain
pump. Follow the manufacturer’s directions.
What About
Solar Pumps?
We have been
hesitant to stock solar pumps because of their inconsistent performance.
They are kind of touchy. But they are getting better. The pump itself
is special, using brushes instead of a magnetic rotor, and the solar
panels need to be powerful enough to push the water high. When we
know more about options (which are getting better) we will let you
know. |