Pond Boss Forums AERATION Should I aerate? Windmill aerator

Uncle Sean - If you are still here following this thread, I think the windmill is a bad idea for a two acre trout pond for several reasons.
1. Trees ""pretty well surrounding the pond"" will likely block the wind wind when you are especially need it to be mixing at that special time in dire need. Keep in mind that the amount of air the mill creates to mix water is highly dependent on the wind speed. As the system ages toward the next compressor rebuild maintenance it takes more wind to generate the same amount of air as previous. ALSO the deeper the diffuser the more wind speed that is needed to over come head pressure of the water over the diffuser. So a 6 ft deep windmill will need less wind speed than in a 12 ft deep pond to create the same amount of air volume. Slow wind less that 5mph generates not enough air for some depths due to water head pressure. Plus wind speed is not constant and variable, as in gusts, so air pumping often is not constant.

2. ONE VERY IMPORTANT NOTE you mentioned "" ability to get a sufficient amount of power to create oxygen" . Generally do NOT count on bottom diffused aeration to produce significant oxygen; bubbling and water mixing yes but not lots of DO is added to the water because of

A. oxygen diffuses into water very slowly due to O2 soluability. Carbon dioxide (CO2) is readily absorbed or dissolved by water (it’s about 200 times more soluble than oxygen!) .

B. The bubbles are in contact with the water for too short of time to get good movement of O2 into water. Diffused aeration is primarily for bringing low quality water from the bottom to the top where impurities are diluted with better top water, gases diffused out, and some atmospheric air (O2) gets added. PLUS the bottom water gets warmed and mixed down by the circulation pattern - thus warming the cool deep water in JUL-AUG may not be good for trout.

3. A windmill will likely not work very much due to low wind days when you need aeration the most. The windmill could work too much too long and do more harm than good at unique times. Aeration with a windmill is controlled by when the wind blows and not necessarily when the pond needs mixing the most.

4. One windmill will not mix very much water = surface area. The size of the surface boil and water flow is dependent on air volume. Less air = less volume mixed and there is a limit to the mixing spread and area based on air volume input. Generally from my experience with mills one mill will mix at most and optimum about 3/4 acre of water in a square steep sided pond located well in open area well exposed to full wind. Often the max mixing is more like 1/3 acre at most. So when air volume is not constant water mixing is variable. The more air volume, the stronger the water upwelling, and more total water that is moved. So IMO in your tree sheltered conditions don't count on the windmill mixing more 1/3 acre of water.

5. A solar aerator can be built so operation is with a timer operated with batteries. This can produce full air volume maximum water mixing whenever your set the timer.; not dependent on variable wind speed. You control when the system runs not Mother Nature. For trout night aeration operation is often best

6. A solar aerator may not be all that much more money expended compared to total windmill cost when you consider the results of the windmill may be killing some trout that have to be replaced. Difference in cost may not be not that much if you assemble the solar system yourself as explained in past post by PB Forum members who built their own Solar System.

7. My questions for you is how old is the pond?
How long has it had trout?
How long have trout been dying during the summer?
How many trout die each year due to low DO?
Where and how does the spring water enter the pond? Any idea how much spring water flow volume is there into the pond?
Is there enough spring flow enough to provide a small cool water refuge for the majority of the trout.
In the long run based on spring water flow you may be much better off spending you money on building a successful a small (0.1-0.2 ac) trout pond that does not aeration. Plus a small 0.2 ac trout pond would be much easier to manage and watch the overall trout population compared those in 2 ac. Then use the large pond for other mixed fish species such as forage fish, yellow perch, smallmouth bass, and some put and take trout.