Pump recs

On Thu, 07 Sep 2006 07:23:53 -0700, Fredric E. Rose, Ph.D. wrote:

I'm limited to the diameter of what comes out of the pump, right? The 2
pumps I tried are both 1/2 inch. I've been looking a the OASE Atlantis and
Aquamax lines, which can vary from 1.5" to 2" outlets depending on the pump
size. Those start at 700 gph but from there goes up to 1000, 1200, 1500,
and 2000gph. What size would give me good water movement without too much
circulation: I don't want to have so much suction that my goldfish get stuck
to the pump!

Half inch pipe won't give you much flow at all if the pipe is any
length and you have about 9 foot of it. You can get adapters and they
can be used either way round. If you have a spare few inches of pipe
I'd put it on your pump so that the outlet is just above waterlevel
(supporting the pump if necessary) and see what you get, it should be a
lot more than you get out of 9 feet of pipe.

We have a T8000E and that gives about half an inch of water in our
stream which is about 8 inches wide. You can see it in the link below
but it's litres/hour so it's a bit under 2,000 gph. It pumps through 2
inch solid pipe and also goes through a filter but it might be a bit
too powerful for you.

http://www.pumpsandspares.com/blagdo...pumpselect.php

It's really hard to select a pump since it depends so much on the size
of the pipe and the head. Generally the low wattage ones can't deliver
a high head when compared to a high wattage pump moving the same
volume.

There is a friction loss chart he

http://www.plumbingsupply.com/flowchart.html

For your stream 10gpm would probably do but if you look at the chart it
says that 100ft of 1/2inch pipe generates a head of over 80ft. So your
9feet will generate a head of just under 8 feet. If you then look at
your pump specs you should be able to see what sort of flow it can give
at that head. The real figure will be somewhere between the max your
pump can supply and what it can supply at 8 ft since the flow has
slowed so the friction loss will be lower. As far as I'm concerned is
just guesswork but there are equations around to calculate it but you
do need values for your pump.

Now if we look at the friction loss for 2inch pipe at 10gpm it 0.21 ft
so 9ft of that will give you a head of very roughly an inch at that
flow. This chart is for solid pipes though and their friction loss is a
lot lower than flexible pipes, the ribbed ones at least. Even the
ribbed pipes with a smooth inside isn't totally smooth especially when
it's bent and that creates unwanted turbulence.

If it was me I'd put in some 2inch waste pipe, black is less visible
and the algae will grow on it, and get an adapter and just try the pump
you have. Then you will have an idea of how much flow you want and you
can just get an appropriate pump.

There are some pics of our pipes he

http://www.infohitsystems.ltd.uk/Gal...to.sh?path=PND

The pipes coming out of the pond are hidden now. The flat stone was put
over the top and the plant in the corner has grown out over them. We
have two feed pipes, one for the filter and another one that goes to
the top of the stream. The filter also feeds to the top of the stream.
We switch the waterfall pump off at times and just have the filter pump
running.

--
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail ngpsm4 (at) infohitsystems (dot) ltd (dot) uk