"Tony Bull" wrote in message
om...
"Gary Roberts" wrote in message
...
I have tried everything I can think of - have got pump running 24 hrs a
day
with a UV filter supposely killing algy - throw pond salt in every day
(should I be doing that) - we haven't got any blanket weed or snails -
about
8 very large koi and 8 small ones live in the pond - would love it to
look
crystal clear.


Here are some more thoughts on the subject.
Anecdotal information suggests that only barley straw and not wheat
straw is effective. One theory is that the straw decomposes and forms
humic acid. The humic acid oxidises the well-oxygenated water to
hydrogen peroxide. H2O2 in very small concentrations is fatal to
algae.
My friend who is a fish biologist suggests that daphnia breed in the
barley straw and consume great quantities of algae.
Neither theories seem to explain why only barley straw is effective.
Unfortunately fish consume great quantities of daphnia!!
I have found that the small bags sold in garden centres are
ineffective. I use two nets that have each held 3kg of seed potatoes.
I place a 10cm stone in the bottom of each net and stuff the barley
straw on top, packing it quite tightly. I then tie the bags under the
return from the filter or under the waterfall from one of my
fountains!! My pond had been green for two years when I used the
barley straw. I used it in August last year, and it cleared in about 6
weeks. This coincided with a drop in temperature so the real test was
this spring when a rise in temperature did not bring about the
expected algal bloom. The straw has also cleared my friend's pond,
again in about six weeks. My wife also gets in the pond in November
and physically removes silt and dead leaves. We generally remove about
four barrows full (my pond is about 5 metres diameter.
I hope that this is of some use to all
Tony Bull
www.caterpillarfountain.co.uk

I have also tried barley straw but found that it was to unsightly for my
liking. I still think that the OP would do better to fit a biological filter
of an appropriate size, he could then buy a seeding material (use to be in a
packet costing coppers) from any garden and pond shop or maybe if he knows
someone with a filter he could use a bucket of water out of the bottom of
their filter, he should find it's up and running within two or three weeks.

H.