Thanks for the info Bill. I'm pretty sure the vane breaking reasoning did come from Gast a few years ago. I assume in your last paragraph you mean aerobic bacteria. With our management practices we do sometimes deal with the near sewage lagoon. Years of direct agricultural runoff, or ponds dug in peat bogs are too common. This along with the augmentation usually biweekly of bacteria makes continual operation sensical. There is such a wide range of practices with aeration dependent on so many variables and experiences among installers. With high BOD, we shoot for theoretical complete mixing 3-4 times a day. Using gast pumps or blowers and Mix Air diffusers, this can be easily accomplished. Our independant test data on the bladder diffusers or stones that we've been given makes me wonder what kind of turnover rates someone can get by running for only a percentage of the day. However, the desired end result of bottom DO levels above 1ppm are usually the base requirements for a system, but if bacterial colonization is at depth zero and DO isn't maintained even a few centimeters off bottom, this would slow or stop decomposition. I know when we drop a DO meter down, we may not be reading at this exact of a distance. We try to adopt the wastewater concept in our management practices, of course to a much less concentrated extent. Hopefully I've made sense, and this stirs some other info sharing and experiences. Throwing algaecides, dyes, and other things into the mix keeps things interesting. I like to keep an open mind on any subject, and have picked up alot of info on this site, it's not just for new pond owners,although I often refer clients here if they are computer literate.
Robert B
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