a pump involves a couple of easy steps:
Determine the MAX HEAD in feet (the height to rise above
2) Determine the FLOW RATE in GPM (gallons per minute)
Multiply width of the stream, or if you have no stream the width
of the waterfall spillway outlet (in feet) x 36* GPM = flow
needed in GPM.
*36 GPM is a fixed number that you always use.
Step 1 - Let's
say your pump inlet is 2 feet below the waterline in your
skimmer. Let's say the top of your waterfall where the water
comes out is 6 feet higher than your pond level. You
measure your Max Head from the waterline and not how deep
your pump inlet is.
Your Max Head (how high
to lift the water) is 6 feet
You can see
from the Pump Comparison Chart
that a 6 foot lift is within limits under the
Max Head column
for any pump on this page.
- Now we need to
find the right GPM flow rate. Let's say your waterfall outlet
opening is 24 inches wide, or 2 feet, and you have no stream.
Multiply 2 times 36 GPM and you get 72 GPM.
Your flow rate is 72
GPM (gallons per minute)
Your flow rate is 4,320 GPH (gallons per hour)
Look at the
@ Feet of Head columns and notice there are
values from 5' to 30' and since your water has to rise 6'
feet you can't use the 5' column so just move up to the
10' column of values. Important: Always move up to the
next higher column and never lower!
down that column looking for a pump that provides the GPM
you determined you needed which was at least 72 GPM. The
first one that fits your need is the EP6700 with a flow
rate of 80 GPM at 10' of head.
pumps fit your application you can compare the cost to operate,
outlet size, etc. to finalize your selection. The worse
thing you can do is get a pump too small to properly turn
over your water fast enough to keep it well aerated and
your biological filters working the way that they should.
Important: You can always reduce your water flow if it
is too fast with a valve, but you can never increase it
to make your pond healthier!
will also support a stream from your waterfall no more than
2 feet wide. If you have a stream wider than 2 feet you
need to increase your GPM. The length of the stream is not
a factor. All that matters is how high the water needs to
GPM flow per hour for an Eco Pond is 1.5 times the total
gallons per hour. In this case, (4,320/150) x 100 = 2,880
Gallons So if your ponds total gallons is 2,880 or
less you are OK.
the flow rate of your pump: If you start your pump up
and you find your flow rate is too much, you can always
install an adjustable flow valve on the output line of the
pump plumbing to reduce the flow rate to where you want
it. This will not hurt the pump at all and will also save
on energy costs. The backpressure from this valve will reduce
your energy costs and not hurt the pump in any way or void
the warranty. If you install a pump too small and your flow
rate is to low there is nothing you can do to improve it
except to buy a bigger pump.