I haven't commented on this thread as it has been well covered by some of the other experts. I do want to comment on what Bill and Cecil have brought up regarding the bacteria products on the market for ponds and lack of scientific data to support the claims made by those who sell and use them. These products are popular and there is a lot of money to be made by selling them~ I have dealers who use certain types and blends and swear by the results they achieve. I think just about every aeration manufacture has jumped on the wagon, but with out real factual data we just can't bring our company to market these products. I'm not saying they don't work ~ but how can you make recomendations with out knowing if they work? We have recently hired a PHD in limnology to conduct research that can be judged by peers, published, and presented. We hope to shine some light into this subject as well as to gain a better understanding into the effects of aeration on ponds and their dynamic ecosystems. Stay tuned...