Have treated my 1/2 acre pond three times in the past 6 weeks to kill my algae problem. Have been using 2 gallons of copper sulfate liquid and mixing each gallon with 2 gallons water and spraying around the edges. It does rid the pond in a few days and I keep getting my hopes up, but in a week or so it keeps re-emerging. For some reason this summer I can't rid my pond of the stuff for any length of time. I read a post above that mentioned using Hydrothol may cause more algae growth and I did treat my pond a few months ago with 40 pounds to rid it of a major pondweed problem. It killed the pondweed and I tried to remove as much of the dead stuff as I could with a garden rake. I know any nutrients just cause more fuel so I try to keep the dead weeds and algae removed as well as I can. Am I alone with an algae problem this summer?? It has been very wet and my pond has been overfilled a few times with drainage.