Proper Pump and
Plumbing Sizing for Successful Installation
Choosing The Right Pump:
4 Easy Steps to the Perfect Pump
1. Find GPH by width and appearance of falls
2. Size Tubing to provide best possible flow
3. Find the Total Dynamic Head of feature
4. Choose the perfect pump… or pumps!
how to know how much flow?
First determine total width of spillway(s)
then choose the appearance desired:
•Trickle, ¼”-½” depth of water over spillway, allow 50 GPH for each inch of width of spillway
•Sheet, ½”-¾”, allow 100 GPH for each inch of width of spillway
•NIAGARA, 1”-1¼” deep over weir, allow 200 GPH for each inch of width of spillway
16” weir at low flow: 16” x 100 = 1600gph
30” waterfall, high flow: 30” x 200 = 6000gph
this about Tubing Size?
It makes ALL
but what does “restrictive” really mean?
•eliminate damaging “water hammer”
•reduce stress fatigue in pipe and fittings
•lessen workload of pump and
•Minimize flow losses due to friction so, less friction means lower head and greater water flow per watt
but, is it really
all about the size of your hose?
just how much
Filling the 10 Gallon Bucket in…
•30 seconds = 1200gph
•15 seconds = 2400gph
•8 seconds = 4500gph
•6 seconds = 6000gph
The surface area of the small circle is 2π ; the larger is 4 π, twice as much surface area, so we might expect about double the friction in the larger circle.
The volume of the smaller circle is π ; the volume of the larger 4π, four times as much volume, so we can expect quadruple the flow through the larger pipe, with only double the friction. The larger the pipe, the greater the difference.
Pipe & Hose
To minimize friction and maximize flow and longevity
Then, Choose the perfect pump…or pumps!
following Pipe & Hose Sizing Guidelines*
Add 1 foot of head for each 25’ of hose;
Add 1 foot for every check valve;
Add ½ foot of head for every other fitting;
Add to Static Head. Round up for THD.
Static Head+[(Run+Fittings)/100 x Friction Loss
For a 4’ high x 30” waterfall,
find the Total Dynamic Head, with:
6000 gph through 25’ of 3” flex (chart)
1 - 90° elbow
1 - male/female adapter (bottom right table)
1 - swing check valve
4 + [(25 + 11.1 + 6.5 + 27.1) /100 x 2.66] = 6 TDH
So what? Do tubing
size and head really make a difference? YES!
4’ high x 30” waterfall, 6000 gph, 25’ of flex PVC, 90° elbow, male/female adapter, check valve:
3” 4’+ [(25 + 11.1 + 6.5 + 27.1) /100 x 2.66] = 6’ TDH
2” 4’+ [(25 + 8.6 + 4.5 + 19.1) /100 x 19.12] = 15’TDH
4’ high x 30” waterfall, 3000 gph, 25’ of flex PVC, 90° elbow, male/female adapter, check valve:
2” 4’+ [(25 + 8.6 + 4.5 + 19.1) /100 x 5.31] = 7’ TDH
1½” 4’+ [(25 + 7.5 + 3.5 +15.2) /100 x 21.52] = 11’ TDH
1¼” 4’+ [(25 + 6.7 + 2.8 + 13.1) /100 x 52.41] = 25’ TDH
and the difference is?
4’ high x 30” waterfall, 6000 gph, 25’ of flex hose, 90° elbow, male/female adapter, check valve:
* Need to raise back pressure w/valve to 11’ head
Tech Talk - Suction
•Pondwater contains dissolved air, just like champagne contains dissolved CO2
•Drop the pressure – pop the cork – and the
gas comes out of suspension, creating foam
•Likewise, low pressure at the inlet of a high head pump operated below its minimum head draws air bubbles out of the pondwater and into the volute
•The bubbles IMPLODE under high pressure at the pump’s outlet, damaging volute and impeller
•The motor, spinning the
impeller in froth instead of a solid column of water, overspeeds and burns out
Choose the perfect pump… or pumps!
Choose the type of pump that provides the desired flow in GPH Through the optimal tubing size at the correct Total Dynamic Head for the least wattage consumed.
so, what types of pumps are there?
•Direct Drive -- costly to run, only necessary for high head.
•MagDrive -- small, simple, one moving part, easy maintenance
•Asynchronous -- for high volume, low head, v. low watts
•Axial Flow – DOUBLE the flow for same wattage, v. low head
Submersible Pump Applications
Pro-Very Efficient, High Volume, No Cavitation
Con-Limited Application, Requires Large Tubing
•MagDrive – Low to Med. Head – to 12’ TDH, 5 psi
Pro-Efficient, Dependable, Simple, Replaceable Impeller
Con-Bidirectional, inefficient impeller, magnet size, noise
•HY-Drive – Medium Head – to 24’ TDH, 10 psi
Pro-Asynchronous, Very Efficient, Dependable, Very Quiet
Con-Non Replaceable Impeller, flows drop off at high head
•Direct Drive – Medium to High Head – to 50’+, 15 psi+
Pro-Asynchronous, Efficient Impeller, Great Head/Pressure
Con-Seals, High Power Consumption, Heavy
you’ll want the lowest head pump possible.
The Laws of Affinity state (more or less) that:
you SQUARE the power to double the Volume;
you CUBE the power to double the Pressure!
2 times the Volume = 22 = 4 times the Wattage
2 times the Pressure = 23 = 8 times the Wattage
So, Cut the Volume, really drop the wattage
Cut the Pressure, REALLY drop the wattage
to cut the
volume, how about using
does a few $
but wait – there’s more!
Advantages of Redundancy
in ADDITION to the savings ???
•Less chance of night circulation failure
•Removal for servicing/repair
•Alternating use to save wear•Elective flow at night/ for parties/ vacations/ off season/ off hours
so, is it worth…
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