“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, with gallons per hour around zero.
So if you need to pump, say, 200 gph at 72″, you will probably
need about a 300-600 gallon per hour pump to do the job. See a
“pump curve” for the amount of water pumped to various heights.
Major pump manufacturers like Cal Pump, Fountain Tech
Pumpsand others, include pump curves on their boxes,
brochures, or other literature. You should take a good look.
“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. When buying a pump for the first time
or when seeking a replacement pump, it is essential that you
know how many gallons per hour you want to pump and at what
heighth (head). Water Volume: The total volume that you will be
pumping is controlled by a few factors. One factor is the size
of the pump, as covered above. But you also must consider how
wide your tubing will be. Tubing is measured in two ways: inside
diameter (i.d.) and outside diameter (o.d.). Very skinny 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 1/2″ inside diameter tubing, they are only
getting what they consider a trickle. Well, we had an engineer
do some calculations for us to illustrate the problem. Using a
300 gph pump with 1/2″ tubing is going to restrict your flow to
253 gallons per hour. By increasing the pump to 450 gallons per
hour, but still using 1/2″ tubing, you will increase volume only
slightly, to 264 gallons per hour! The lesson is this: 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 1/2″
i.d. tubing, for instance, but you are running the tubing twenty
feet from the pump, it is a good idea to use 3/4″ 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. When you buy a fountain,
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 recirculate
the water once an hour, more often if possible. Thus, if your
pond is 500 gallons, try to buy a pump that will recirculate
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 large 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?
Fountain Mountain,
Inc.receives 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 you buy as many as possible
battery-powered fountains at a store like Wal-Mart and remove
the pump from the fountain. You get the whole fountain for as
good of a price as we could get you these specialized pumps all
by themselves, and we don’t have to order 500 of them at a time!
What About Solar Pumps?
Fountain Mountain, Inc. also receives many inquiries about solar
pumps. These are okay, but we have decided not to carry them
because of a few reasons. For one, these pumps, like
battery-operated ones, just aren’t so trustworthy; they don’t
last as long as a regular pump. For another, they go on and off
constantly depending on quality of sunlight, passing clouds,
etc. unless you buy one that works on batteries and solar. Then
you have to keep replacing batteries. Also, the ones that work
on both solar and batteries are expensive for the little bit of
water they will pump. Finally, what decided it for us was that
some companies allow credit card charges for all of their
products except for solar pumps. This means to us that the
companies are afraid of too many returns from customers.
Eventually, the technology might be there for us to sell them,
but we are not quite ready. 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 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, pumps are supposed to be cleaned every so
often by opening up the impeller case on the fountain pump.
Follow the manufacturer’s directions.
