"Easynews" wrote in message
m...
Dear all,
We have a new large-ish wildlife pond, 10m (30 feet or so) roughly
circular, and about 5 feet deep in the middle. We have a problem with the
local soil being heavy red clay- as a result the water is permanently a
greyish-brown colour and water can't penetrate to plants. I've tried
floculating chemicals like "pond clear" but it has little or no effect- I
think we would need gallons and gallons of it for this size of pond. Can
anyone suggest a filter pump that can help us, without affecting the
wildlife? If not, then what filter/pump would clear the water the
quickest, that we can run for a short time before planting up?
Paul D.

How new is the pond? Have you given it enough time to settle own it's own?
No mechanical filter is going to be able to strain out the suspended
particles if something is constantly stirring up the pond bottom.

We can assume that your pond is approximately cylinder shaped, we can
estimate that it contains about 3500 cuft of water, or about 26000 gallons.
Further if we assume nothing is churning up the bottom of the pond, and we
used flocculating agents, it would take 21 bottles of pond clear (1 bottle
for about 1200 gal). Not a cost effective solution in my opinion.

I think your best bet is to figure out what is stirring up the pond bottom.
ducks? raccoons? koi? catfish? If nothing is stirring it up, then try this
experiment for giggles:

Fill a bucket with some muddy pond water, set it aside, see how long it
takes for the stuff to settle on it it's own.
There is a formula to calculate the rate at which suspended solids settle
out of water. But I'm too lazy to look it up. So this experiment should be
good enough, for example if it takes 20 hours for water in a 12" bucket to
clear up, it would take 100 hours to settle in 5ft deep water. If you really
want to know the formula, an engineer at your local water or sewer
department would know.

-S

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"There ought to be limits to freedom," -George W. Bush Nov, 1999