Ted I am not sure where Koender's is with their dual diaphragm model. As a dealer, I have not heard or seen any promotional material or prices of dual diaphragm windmills as of 11-15-04. I was notified that they now have an office in Springdale, AK 1-866-471-1614; Randy Meier- Koenders USA.
I still contend that that if electric power is within 600-1000 ft of a pond for $750 to $1400 one can buy a 1/4 hp aeration system that far exceeds the ability of a windmill, single or dual diaphragm. One needs a good windspeed (apprx 15- 20mph) to get those advertised maximum air volumes at deeper depths. Air generation for those windmills is on an increasing scale based on wind speed. One may get 3 cfm at 9mph with no head pressure (0 depth). But when you start increasing the water depth over the diffuser the the wind speed has to increase to compenstate for the increased head pressure.
