leave it alone and put plenty of oxygenating plants in. you also need about 1/3 of the surface covered with leaf[lily is good for this]. If you have a filter you can get them with an inline uv light that will kill the algae.

Mine is cloudy for about 2 months in the spring then it stays clear untill about April next year. if you have a fountain make sure it is not stirring up the sediment as the constant flow of nutrients will also help green it up.

Hi, jim. I have had a 5000 gallon pond for over 20yrs and I think there is no way of stopping pond water going green. I have a filter with uv light which is running 24/7 and it still goes green on occasions. It doesn't help if its in full sun and, I agree wth seaburngirl. You can buy chemicals that will clear the water, but it will eventually green up again. Don't know if you have fish, but if you do, don't worry, the fish don't mind and it will not harm them. I know its nice to have a nice clear pond, but stick with it. hope this helps and good luck.