On 25 Aug 2005 13:06:03 -0700, wrote:

hey all, we built a 3-3.5k gal pond this year and it's been up and
running for about 6 weeks. we have it piped through a ultimate fluid
art filtration system (rated for 5k). it's got the vortex, bead
filtration, uv (36w), etc. the pond gets full sun and algae has been
an issue since the first week. i have about 20 koi in there now
(4"-10") and they seem ok. i'm thinking of dropping a stronger uv in
there but have noticed that some of the fish are feeding on the algae
and all are always hungry (i swear i could feed them, turn around and
feed them again 30 mins later). they are growing quite well (all were
about 4-5" when i got them and some have doubled in size in this time
frame). PH has peaked in the low 8's during the day dropping back to
mid-high 7's at night.

What sort of algae is this? You say your fish are eating it so I'm
assuming string algae. This isn't bad providing it doesn't get out of
control and become unsightly. Are you adding potash? A tablespoon a
week per 1000 gallons will help the plants take up the nutrients and
starve the algae out.

should i be concerned and go with the larger uv? also, how often
should one be backflushing the system? i've done it a few times now
and it didn't seem too bad. shouldn't the system be taking care of the
algae yet?

A uv will only help with green water algae, it has no effect on string
algae since it doesn't go through the uv.

Is your filtration effective? You should be getting solids in the
bottom of the vortex and not on the bottom of your pond and if they are
left in the bacteria will convert them to nitrates and feed the algae.

Some of the bubblebead filters here
http://www.bubblebeadfilters.co.uk/filter_main.html can be put on a
timer to switch the pump off for fifteen minutes every day and a valve
then opens and cleans the beads. You should see dirty water coming out
when you backflush your bead filter and you can safely change 300
gallons in your size of pond a week.

You say you feed three handfuls of food twice a day but how long do
the fish spend eating this? I like to see it all eaten within two
minutes although some people prefer five. Cutting down on the feeding
will certainly help. I'd be happy with your stocking level providing
the about 20 is 20. Stocking at 1000 galloons for the first fish and
then 100 gallons for each other one is what I see recommended in the UK
but you would certainly have fewer problems with Pauls recommendation
of one fish per 200 gallons. A lot of people go well over this
without any problems, especially if they have a vegifilter.

--
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