Hi all, I started my aeration early this spring and things seem to be on track. I was running at night as that seems to be the consensuses during the hot summer days. Now around here in Missouri our nights have been dipping down to the upper 40s on occasion but the days are remaining 80 or so. Last night I decided to start the aerator at about 5:30 am and run it 8 or so hours during the morning as maybe it wont cool the water too much. I have not checked my water temp.
Is this a good thing to change this time of year? I don't expect the water will "turn over" since I have had air on it all summer. Once it gets cold I will only run the shallow when I need to keep it from icing.
Thanks
Dave

Here is a Bill Cody quote: "A common time to stop aeration is when the water gets 50F or high 40's or near these temps. Then the pond usually fully circulates especially if it receives some wind action. Fall circulation stops when ice cover forms and water is typically 39F from about 14"-20" to the bottom."

from this thread: http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=307498


You can still run your air in the winter, but you'll need a diffuser in shallow water (1-3 feet typically) to avoid super cooling your pond.

Thanks DrLuke for that thread. I will continue running mine but I think I will go ahead and run it more during the day since it is cooler at night. I don't know that it will gain me much during the day vs night but I do like watching it run and move the water.
Thanks
Dave

Then what about ponds in the south FL,GA,AL,MS,TX ect. where we do not get ice coverage on the water and the coldest the water may get is low 50's high 40's?

I don't think that they will "need" to be aerated during the winter but......

That is a good question for Highflyer to answer with data. He has a deep pond, and he has an O2 meter, AND he does not have an aeration system. It would be interesting to see if he's taken readings down deep during the winter to see what his O2 readings are when compared to the top 8' of water.

For instance, I checked a pond last week. It has an aeration system, but it was dug deeper post aeration system installation and the air stations were not re-positioned. The diffusers/air stations were at the 6' and 8' depth. The pond was dug to 18'. The concern was where the threshold of 5mg/l O2 was in the pond. There was still 5.0mg/l O2 at 12' down, but the O2 levels quickly dropped to 2.2 mg/l at 18'. Water temp at surface was 70°F and 68°G at 18' depth.

On a side note, the aeration system was left in the pond with all the water as the pond was dug deeper. Clay pond that needs no compaction. Enough clay material washed out of the bucket as it was being dug to cover the air line and diffuser air station closest to where the digging was being done with over about a foot plus of clay. That airstation was within 40' of the digging. The airstation that was 80-90 feet away still had clay over it, about 6"-8".

Another reason to drain the pond prior to making it deeper.

Our coldest month the average low is 24 and the average high is 52.

I have no idea what my water temperature is.

Do I need to worry about super cooling with this temp range?

My pond is 1/3 acre, 15 feet deep with two aerators at the very bottom running 24/7 since I filled the pond.

Good question on aereation. I'm a lot further north of you but I questioned at what point was best to stop mine.

I finally decided to stop when I thought there was no more chance of pond turnover and night time temperatures were such that I thouht I was cooling the BOW rather than just mixing it. I wanted to feed as late into the fall as I could and felt like cooling the water with cold surface temperatures was counter productive from a feeding standpoint.

Not saying what I did was right. Just what seemed right for me at the time. I also would like to have better guidlines on when to stop.

In my 3+ acre E Texas pond I checked temp and DO yesterday, it was a really nice day. My water temp was 52.5 at 9'(my probe is limited with a 9'cord). The water temp was 52.5 from 9' to near the surface where the surface was 60. Pond average water depth is 7' with the deepest being 10 and 12 foot when full pool(pond has two different pool areas) The DO was 8.8 or 76.6% from top to bottom except along the windy shoreline where the DO was 98 to 99% at 3' to the land. Pond aeration(diffusers) were turned off about 5 days ago or just before this last cold front. As I understand it, at my sea level and with my water temp steady 52.5 from top to bottom, an 8.8mg/L or 76.6% is good to go. Diffusers will remain off till late Feb or March

All,
When I get back to Texas. I'll test as well. As of Friday, my surface temps were still in the low to mid 60's so I would expect to still have a thermal cline at 12 to 14 feet. There has been some extra wind this fall and one or two cold snaps, so who knows. I did test once last year during the winter, But I don't have that data handy. As I recall, I still had a thermal cline, but I can't remember how deep it was. At that time, our water was still warm to remain unmixed.

One thing to be cautious of is quick temp changes from any source (rain , super cooling , aeration , wind, etc.). Most pond fish do not like fast temp changes which can be lethal. If you quickly and substantially change the water temp in the refuge zone (where fish are holding) be ready for potential problems.

I think I run into that problem on occasion in my 1/10th acre sediment pond . Sometimes after a big rain event I will find a few dead fish in the even tinier pond ahead and connected to it.

This pond catches about half the watershed for my main 3 acre pond. So during a large rain event it could have several full water exchanges in a matter of hours. If a rain comes hard and cold with rapid inflow, I know it must stress the fish at best.