It is most important to remove nutrients from the pond. There are a few ways to do
this:
clean the filter removes bacteria and anything caught in the course filter
use plants to suck up nutrients and turn it into veggie growth (veggie filters)
UV damages the algae so it is filtered out (easily with polyester batting) or fine
foam filters
water changes (iffy)

I use only plants in a veggie filter. the UV damaged algae gets caught on the roots
and removed

clean the UV bulb or glass surrounding it so there is good UV transmission. UV bulbs
should last quite a while. water changes work if your water is VERY low in
nutrients. I have lake water that only has a bit of bicarb in it, no nitrates for
example.

if/when you get fish get the highest protein or feed freeze dried krill or fish. koi
cannot digest carbs so carbohydrates are in and out of koi and just foul the water.
most people overfeed their fish. corn leads to fatty fish and fatty liver disease.
koi need proteins for building muscle and fat for energy. the kind of fat is water
based and so will go rancid quickly, the good food needs to be kept in a freezer to
prevent this.

INgrid


On Mon, 20 Apr 2009 19:56:50 EDT, "JB" wrote:
What kind of filter are you using? Chances are you need to disassemble it
and give it a good cleaning. Removing the "gunk" - leaves and stuff - from
the pond is also a good place to start. Don't know if I would have left the
u/v on all winter. I thought those were best to combat the spring algae
bloom but what do I know, I don't have one. ;-)

Got any/many plants? How did they do over the winter. Now's a good time to
divide them if they've gotten too large for their containers.