Pump Sizing help

[xman]

Hi,

I am setting up a small pond/water garden and am trying to size the pump. The pond is preformed liner 140 gallon, the waterfall is about a 1 - 1.5' above the water level in the pond. The stream is 3 ft long from the weir (the weir is actually another small preformed shell that is about 15 gallon) to the pond.
1/2 inch tubing to connect the pump to the weir.
The width of the weir/waterfall is about 8" - 10" and stream is about 8 inches wide too.

I am looking at a Danner mag drive pump. A couple of small gold fish and a few water lillies is what is planned to go in the pond which is in full sun.

What gph should I go with? I do not want to over-size or under-size.
Any help greatly appreciated.

Thanks,
xman

 

[DrCase]

Look for low wattage first...300 gal per hr would be good

 

[xman]

DrCase,

I remember reading somewhere today that you need atleast 100 gph per inch of waterfall width. So at 8" waterfall/stream would I not require a pump > 800 gph? or is this not true?

thanks,
xman

 

[DrCase]

I wasent paying att ,,,if you want good water fall action you are right,,Go for around 1000 gph so you have some extra

 

[koiguy1969]

exspecially with 1/2" hosing... if the flow isnt quite what you want move up to 3/4 or 1" hose, although you should be o.k... the larger tubing will be less flow restriction

 

[xman]

Koiguy,

How do I move to a 3/4" hose? the smaller preformed liner that is going to act as my waterfall weir has a 1/2 bulkhead.

thanks,
xman

 

[koiguy1969]

any lowes or home depot will have the appropriate adapters

 

[koiguy1969]

oh...drill out the liner to the size you need, between the pond and plumbing sections you'll have no problem getting what you need.