I read that information also when it can out in their new catalog. That information comes from Jones Fish Farm, Cincinnati OH. I do not think they are completely correct in this statement. I am a long time dealer of the same brand of windmills they sell. There are numerous details to fully explain their dramatic comment.
Constant wind is not necessary to maintain destatification of a small pond 1/4 to 3/4 acre. BUT for odd shaped ponds and ponds Larger the 3/4 acre the windmill is not sufficient for complete pond circulation. But common sense should tell you that you should have open exposure to wind from at least three directions for the windmill to be minimally affective.
ALL bottom aeration systems, not just the windmill can induce a fish kill when operated IMPROPERLY. Knowing all the disadvantages of windmill aeration, I say get a windmill for your remote pond. You will have more fish kills WITHOUT the windmill than with it.
I "think" they are trying to scare you into ALSO buying their electric aerator. Since they are the only ones "preaching" this sermon, I also think they are trying to make you believe that their biologists know something everyone else does not know and they are "gifted" above all others. They scare you and don't tell you the "rest of the story". If one really knows limnology and the "product" capabilities you can esily see through this smoke. They are only telling you part of the story to make a point; not sure what the hidden point is yet.
After rereading this and reflecting a little, I think what they are getting at is that during brief periods of very gentle wind or no wind the pond will stratify and lose all its oxygen in the deep water. Then after a day or several days with little or no circulation in hot weather, restarting strong circulation will bring up all this new "bad water" and result in a fish kill. "HOGWASH". These guys severely overestimate the ability and circulation power of their windmill. 1. Koender's Windmills produce weak circulation and upwelling currents; even during stronger winds (compared to electric diffuser aerators), thus recirculating an idle pond after several days will not happen fast when using a windmill unless nature assists in the circulation.
2. Plus, the oxygen loss in the restratified deep layer will not happen in just a couple of days under most conditions (I have tested this). About the only way the oxygen loss could happen this fast in the deep water restratified zone is if a phytoplankton bloom died or crashed or you kill lots of weeds or algae all at one time. Then the tremendous decompostion process will "RAPIDLY" consume oxygen and reduce it to lethal levels for the fish.
