For the last 2 years I had a pond that is about 25 feet wide and a parts 9 feet deep. I never had a probleem with green water in it. I have had trout, bass and catfish in it. Over the winter I decieded to expand it a little. I added another 3800 gallons of ponds (2), creeks (3) and waterfall (1). I drained the pond over the winter because there was alot of string alge in it. I got out what I could by hand. After adding the other ponds, creeks and waterfall we filled it up. After about 10 days it started turning green, so I drained and filled it up again. It is turning green again. I did some research and learned the pond is full of nitrate. I went to a irrigation pond just down the road from me and got about 20 various water plant from his pond and planted them in mine. Plants is supose to live off nitrates in the pond and clear the pond up. Is this all correct and if so how long will it take to clear up.