"SkyCatcher" wrote:

I have a 12000L pond with plants & NO fish. The filter/pump/UV are
appropriately sized & I changed the UV bulb 2 week ago - AND the pond if
still filled with green gloopy algae.

UV filters only work on clean water. The UV can't penetrate cloudy
water. Hence it takes a long time for a UV filter to catch up with a
pond full of green water. Also, if the water flows too fast, the UV
doesn't work at all.

I have solved my green water problem with no UV, no filter and no pump.
I use lots of marginal and oxygenator plants, a bale of barley straw and
snails. The algae is all gone and my water lilies are just beginning to
shade the water. My marginal plants and lilies are all planted in pure
clay with no nutrients. There are enough nutrients in the water that
everything is doing fine.

I have a 20,000 gallon pond (17'x47'x2'-4') with just minnows, no Koi.
I put my filter plants directly in the pond rather than in a special
veggie filter. My pond is spring fed, so I need fairly aggressive
filter plants. The pond has stone wall sides (old swimming pool) but I
have greenhouse benches under the water around the outside so I can use
marginals or under water plants.

--
Pardon my spam deterrent; send email to
http://home.earthlink.net/~rhodyman