"pmwebdesigns" writes:

Okay, you guys that have external pumps and uses 55 gal drums are going to
have to help me here. My pump is suppose to push 1500 - 5400 G.P.H.
If I have the pump pulling from the 55gal drum to push water flow in the
pond, I was thinking if it max's 5400 how can I get the water to flow into
the drums being gravity fed fast enough without the drum going dry. I'm go
have 3 drums. One the settlement, one with loads of filter mat and the other
empty with a hair of filtermedia and this one will be the one the pipe from
pump pulls from. Also the pipe going to the pond I was going to have a
venturi thingie set up. Did I explain that? I am so tired.

Hi Priss

You can calculate the head loss from charts like at
http://www.mdminc.com/friction_loss_chart.htm

For 5400 gph flowing into the drum, 100 feet of 4" pipe
will result in the water level in the drum being about 1/2
inch below the pond level whereas 2" pipe will stabilize at
about 12 inches below. This scales linearly so for 25 feet
of pipe the numbers are 1/4 as large. Fittings add to this,
see the chart. Fittings are speced as equivalent feet of
pipe so the calculation is:

1) add up all the feet of straight pipe

2) add the equivalent feet of fittings

3) read the pipe chart at the desired flow rate and pipe
size to see the head loss for 100 feet of pipe

4) figure the proportion for the feet you have (50 feet is
half, etc).

Also this is best case, don't forget things like clogged
filter media and intake screens :-)

Hope this helps

Andy

PS Or you can just use "Rich's Rule": You can't go wrong
with four inch pipe