Pond Boss
Posted By: Uncle Sean Windmill aerator - 02/19/20 07:49 PM
Hi all, I'm thinking if purchasing a windmill aerator for out 2 acre spring fed pond. I mostly want it to help with DO levels in the summer time. I've got a couple questions though.

1) Due to the remoteness of the pond an electric aerator is out of the question and and a solar aerator is too expensive. Because of this remoteness though the pond is pretty well surrounded with trees - the trees don't stop the wind but will they hinder the windmills ability to get a sufficient amount of power to create oxygen?

2) How tall should it be? I'm assuming that because of the trees I'd want to go with the tallest model they make - 24 feet.

3) Will it harm my trout? Should I be concerned about it causing cold water shock in the winter? Will it kick up too much toxic odors at first use?

Thanks,
Uncle Sean
Posted By: wbuffetjr Re: Windmill aerator - 02/19/20 08:19 PM
I have TWO windmill aerators and I would not suggest one. For what they cost, there are on demand solar aerators out there that would probably do a much better job. Especially if you are surrounded by trees.
Posted By: Twar Re: Windmill aerator - 02/23/20 03:35 PM
I have a windmill aerator but would agree that a simple solar setup would work better. I have a 100 watt solar system I put together that delivers air more often and more consistently. I am building a second system that is 200 watts to put in place this spring. I have a handful of the components on hand so my costs are low. For what a windmill costs you could make a much better solar system.

Now if you have trout that live in your Pond year round already I would hesitate to aerate as you might make the deep water too warm.

Do you have trout living year round in your Pond without fish kills?
Posted By: Uncle Sean Re: Windmill aerator - 02/24/20 08:00 PM
Originally Posted By: Twar
I have a windmill aerator but would agree that a simple solar setup would work better. I have a 100 watt solar system I put together that delivers air more often and more consistently. I am building a second system that is 200 watts to put in place this spring. I have a handful of the components on hand so my costs are low. For what a windmill costs you could make a much better solar system.

Now if you have trout that live in your Pond year round already I would hesitate to aerate as you might make the deep water too warm.

Do you have trout living year round in your Pond without fish kills?


Good thinking about making the deep water too warm. Didn't think of that... That's why I asked!

Yes, our trout survive year round. Very rarely do we find a floater but when we do it's typically from some sort of predation.
Posted By: KenHorton Re: Windmill aerator - 02/25/20 02:12 PM
Uncle Sean, I have found that when trout die they will generally not float to the surface. Over the years I have had several general trout kills due to hot summer temperatures and have found only one floater in that time.
Posted By: Uncle Sean Re: Windmill aerator - 02/25/20 05:35 PM
It wouldn't surprise me if we loose some trout to the heat, especially when we get a dry spell.

Interesting about them not floating - that being said we generally have a good number of holdovers in the fall.
Posted By: esshup Re: Windmill aerator - 03/07/20 12:40 AM
Originally Posted by Uncle Sean
Hi all, I'm thinking if purchasing a windmill aerator for out 2 acre spring fed pond. I mostly want it to help with DO levels in the summer time. I've got a couple questions though.

1) Due to the remoteness of the pond an electric aerator is out of the question and and a solar aerator is too expensive. Because of this remoteness though the pond is pretty well surrounded with trees - the trees don't stop the wind but will they hinder the windmills ability to get a sufficient amount of power to create oxygen?

2) How tall should it be? I'm assuming that because of the trees I'd want to go with the tallest model they make - 24 feet.

3) Will it harm my trout? Should I be concerned about it causing cold water shock in the winter? Will it kick up too much toxic odors at first use?

Thanks,
Uncle Sean


The windmill has to be taller then the trees. Another thing to think about is how will you get up there to service the compressor when it needs repair in a year or two?

How far away from electric is the pond? We have trenched in poly pipe underground from the compressor to a remote valve box at pond side, then transitioned to sinking air line in the pond. From compressor to remote valve box was about 1/2 mile.
Posted By: Bill Cody Re: Windmill aerator - 03/07/20 01:43 AM
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.
Posted By: Uncle Sean Re: Windmill aerator - 03/09/20 06:58 PM
Thanks for the response. We're no longer entertaining the idea of an aerator pretty much for all the reasons you stated.

Most of our trout survive the summer anyways so there really isn't much of a need to create 'more' oxygen.
Posted By: gonefishinii Re: Windmill aerator - 03/12/21 03:12 PM
I can't help Uncle Sean with his criteria but my Windmill worked great for 10 years.....it still does but I need to renew the pump which quit last year. i have the stuff to do it with; purchased when new. My pond windmill is wide open from all sides and there is not many times it's no spinning.

I do want to look up solar aerators people have because when I look up what is for sale; they are much more expensive than a windmill aerator.
Posted By: lmoore Re: Windmill aerator - 03/12/21 03:26 PM
In my purely uneducated opinion, a windmill aerator rarely makes sense for the simple fact that the only time it aerates is during times of natural aeration from wind/wave action.
Posted By: John1944 Re: Windmill aerator - 03/20/21 12:35 AM
Mr. Cody. I am replacing my windmill. It has blown over in high winds 3 times in 10 years. Even though I had 4 earth anchors holding it down..I saw in your post above about someone who had directions for building a solar aerator. Can you point me to thar post please.
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