I don't think a UV sterilizer is going to be effective for large volumes of water (in excess of 10K-20K gal). If it is I would like to see proof or data that back up the claims. UV sterilizers can be problematic in that the bulb in unfiltered water can fairly quickly form surface films on it which reduces the effectivenes of the UV. Regular Cleaning the bulb in your situation would in my opinion be troublesome. Chelated copper products are effective on many species of phytoplankton, although the entire pond has to recieve a uniform dosage of the herbicide. This could work in your situation but it would be no doubt require annual or semi-annual treatments since the algae will keep reoccurring. Long term benefit or cure for your problem would be a pond daining and then sludge removal. Bottom sludge and deposits have over many years have created a large nutrient sink which is likely the cause of dense planktonic algae blooms. Since the pond sits at the bottom of a hill it is prone to accumulation of excessive dead and fresh organic materials plus probably some fertilizer runoff. Remove or eliminate the cause (excessive nutrients) and then you will naturally minimize the problem.
Last edited by Bill Cody; 07/29/08 09:54 PM.
