jixxxler,
How old is the pond? Have you noticed any black muck on the bottom when you rake? I would install bottom aeration and also use microbes. Bottom aeration is available in 2 types. Windmill and electric compressor. If you are interested in a windmill you better buy before April 1, 2005 because Koenders will be raising prices again $350.00 which is making it difficult for us dealers selling them. The electric compressor system works well and you will only need 1 diffuser sitting on the pond bottom. \:\)