bassman...
You asked about aeration. Bill is correct, the higher the temperature, the less oxygen can be held in solution.
I was concerned with my pond's aeration after my Uncle's 20 ft. deep pond had a major fish kill (lack of oxygen) when the pond stratified and turned over when a cold front cooled the surface water.
I purchased a 12 ft windmill from
www.malibuwater.com which is a supporter of this site (see products). Other companies sell a similar windmill or even the same product. It takes a lot of simple bolting work to put one together and makes for a good weekend project.
The windmill operates an air compressor and has been fantastic. Somehow it is engineered to turn out of the high winds to slow down to protect itself. I have had it for over 2 years in Oklahoma and so far I am impressed with the duribility. They provided a spare rubber diaphram which I have not used yet....
It does not take much of a breeze to turn the windmill.
Now comes a dig.... If the wind stops blowing for several days, will the pond oxygen get too low? Also, if the wind is blowing.... do you really need the windmill, will not the wind on the surface keep the pond aerated? I will never know the answers to these questions as the wind never stops blowing in Oklahoma.
The malibu site offers other options and provides a good discussion of why you need to aerate for other than oxygen levels.
One thing for sure, a 19 ft pond has a potential of stratification and aeration prevents statification.
Good luck and happy ponding.
