Concerning Southern ponds, just how hot is too hot? I recently installed an aeration system and after a month or so of running 24/7, the water is finally looking better and starting to get a little clarity back (Secchi depth was about 12" soon after starting but now is up to about 18") However, with the aeration I now have zero thermocline and yesterday temps were 87 degrees top to bottom. (Avg depth 6-7') I realize that is getting close to the upper limit, however, you would never know it by the fishes behavior. Everyone seems to be thriving and feeding is just as strong as it's ever been. Which begs the question, just how hot is too hot? Do I really need to switch to a nighttime only schedule even though everything seems to be fine? I'm just wondering if Southern based fish are maybe better adapted to the heat and therefore can tolerate higher temps than they would elsewhere? What do you guys think?

Each species of fish has its own temperature tolerances. What species do you have in your pond?

My fish do the same thing. Last year I was hitting 99f on top before aeration and they were doing good. I run strictly at night for 9 hours and my temps are low 80s with just a couple degrees difference top to bottom in 11'. I've also added dye this year to help shade the deeper water. I dont know the answer to the question, but by the time you find out, it may be too late.

I try to not hit the mid 80's (midwest pond). As my pond warms up, I start moving the aeration to night time. Keep in mind that my aeration system can still turn my pond over several times in a 12 hour period. It's important to keep the pond turning over at least once a day should you cut back the run time and twice a day makes me feel more confident.

Mike's southern pond has multiple species so his experience should cover most cases in general. But, his high 90's may pose problems in a different BOW with different variables.

IIRC, on one of the Wednesday evening PB live videos, Mr. Lusk answered the warm water temp question with a basic concern of anything in the high 80's (EDIT: He says keep it below 83F to say on the safe side See my next post). He was probably being conservative, but that's were I hang my hat too.

OK, Check out the video. Mr.Lusk talks about an example at 21:58, again at 56:40 AND the general rule of thumb at 1:00:48.

Watch the whole thing...your brain will grow substantially regarding the space allocated for pond aeration....

https://www.pondboss.com/news/facebook-live/7_18_18--aeration-in-summer-months-with-matt-rayl

Thanks QA! I plan to watch in full shortly.

QA, watched the video and had totally forgotten that I actually participated in that one and Bob even answered one of my questions at the time! Bottom line from that episode is that I am definitely on the precipice of a disaster if I don't change something soon. So, starting tomorrow I plan to go to a 9PM to 9AM schedule and see how that impacts DO and temps. Somehow I need to reestablish some sort of a thermocline and provide a cooler refuge area for them to escape to. From what they said in the video, it should only take a few days to do so. Will update as soon as I see some changes. Thanks again everyone for your input!!

Well, it's been three days now of me running only at night, (9PM-9AM) and my situation has only gotten worse it seems. My temps are now 90 degrees top to bottom. Fish are still eating and acting normally and DO is pretty consistent top to bottom, but I know things are only going to get hotter from here on. Should I continue my current schedule for a few more days in case it hasn't been long enough yet to effect a change? Or should I cut back on the running time? If it is 90 now, I can only imagine how hot it will be by August or September. Also, if we happen to get a big cooling shower during the day, should I turn it on so that the cooler rainwater on top can be circulated? Sorry to be asking so may questions but I am very concerned that I am on the verge of something bad happening if I don't figure this out. Thanks!

(1 acre pond, avg depth about 7 feet, 3 Kasco diffusers)

I think, with the three diffusers, you should immediately reduce your run time to 9 hours. Continue to monitor you DO levels, and as long as they stay good, continue to cut back on your start time to allow your surface temps as much time as possible to cool. I've cut mine back again for the same reason. Not quite 90 yet, but really close.

Regarding infusing a cool/cold rain, you have to be careful. If the temp drops too quickly you'll stress your fish. Better to let it mix in naturally IMO, than to force it to mix.

Mike W. Suggested in a different thread that he had reduced his run time to start up around 11 pm instead of 9. This should allow some of that hot upper water to cool off some before being turned in. This is worth a shot IF you are comfortable they your pond is getting enough turnovers per day.

I try to not run the air during the heat of the summer when the ambient air temps are warmer than my pond...9am in your parts may get that way.

If it keeps going the way it has been, QA, I may have to shut my bottom aeration down completely myself. Just go with my surface fountain and let the deep stratify until it cools off again. A little DO is better than none at all.

JKS...Last year, before I put in aeration, my surface temps hit 99f. I had to back my boat into the pond and let the outboard stir things for a few minutes to cool it off, having no aeration, the bottom was significantly cooler and I was able to drop the overall temp into the 80s. That's risky tho, because I was dropping temps quickly and also stirring up toxins as well. It worked for me, but my pond was young and hadn't built up a lot of junk yet.

I now have both bottom aeration and just built a surface fountain that pulls water from about two feet deep. I can direct the spray to create a vortex on the surface which allows the upper column to aerate some without pulling up water from down deep. It does seem to help cool the surface a little during the day but I'm still running my bottom system at night...for now anyway. After reading QAs remark about shutting down his bottom system due to excessive ambient temps I'm thinking I may have to follow suit soon.

It's an experiment and not sure exactly how it's going to play out but it should allow for some cooler water to remain at depth where the fish can escape to, at least for a little while until they have to come up for more oxygen. The whole rig cost me less than $200.

Thanks guys! Mike, I changed my runtime to 11PM to 8AM so maybe that will help. I'll continue to monitor DO and see if that is enough to keep it aerated at depth. Even though my pond is 1 surface acre, the sides all slope in pretty good so my water volume is less than a standard 1 Ac pond. With three diffusers, I'm hoping I can get a pretty rapid turnover that will allow me to get by with the shorter runtimes. Thanks again!

As long as you dont go below one full turnover of the pond you can keep cutting back as needed. I'm still getting about three turnovers with 9 hours, so as long as I can run at least 3 hours I'm ok. From now on I'll be cutting back 1 hr at a time as necessary until I reach that mark, then itll be up to the fountain. I'm still holding a 3 degree variance, but the bottom is 82. Got a reprieve yesterday and today with cloudy and rain so it should cool a bit.

With your temps being static top to bottom, I think you have a little bit of wiggle room yet. Just keep watching that variance. When you see the temps start to spread, I think you've reached your limit.

I've been doing some reading on the benefits of surface vs bottom aeration. It seems most of the experts tend to lean toward bottom aeration in ponds with depths of 8 feet or better, and surface aeration for shallower ponds.

That's got me wondering if three diffusers may be way more circulation than you need with an average depth of 6-7 feet, even with an acre of surface. You may want to try to cut back on how much air is getting to each diffuser, or even shutting one down completely (in the deepest part) to allow that section of the pond to cool more and create a refuge for your fish.

It's just a thought and I may be way off base. Maybe someone with more experience will step in and enlighten us both.

Mike, Just checked temps after the 3/4" of rain we got yesterday and after 4 days of running only at night. Temps are now 82 top to bottom. Since there is still no variance, I am going to take your advice again and start slowly cutting back an hour at a time now. Im just relieved that things have cooled off some but I also realize that more heat is on the way. Nighttime only definitely seems to be helping though. I would like to add some type of surface aeration to the mix but I have no power close to the pond. I had to pump air over 300' to get what I have now so, hopefully, I'll be able to get by with just bottom diffusers.

Keeping my fingers crossed for you, bud.

I'm real glad to hear that your temps have dropped!

I will be watching your thread to hear how the thermocline develops or doesn't. I am skeptical that you can develop one in your pond as my 1/4 acre pond is 10 foot deep and the deepest diffuser is set about 8 foot deep and I have seen no evidence of a thermocline in mine.

I know it's been said by some very smart people here that a thermocline will develop if you raise your diffuser off the bottom, but I can't help think that the rising water (caused by the bubbles) will drag water up that is beneath the diffuser and turn it over as well. Maybe my air system is larger than needed which makes the thermocline less likely...I can't say for sure.

At any rate, the thermocline is not that important unless you get to the point that the pond is just too hot. I feel for you folks in the south as you certainly run a better chance of overheating the pond. Using an aeration system in the south to increase carrying capacity may not be very wise. Using it for water quality and general pond health is great, but how would one not reap the carrying capacity benefits? I guess my concern is that if overheating is a strong possibility and you have aeration...wouldn't the fish population/sizes grow to utilize the extra DO water by default? Then an overheating event occurs and there is noting you can do...shutting the aeration off may bring the temps down, but there goes your DO...it seems like a vicious cycle.

I think Mike is onto something when he said "You may want to try to cut back on how much air is getting to each diffuser". I would consider keeping the 3 diffusers and maybe even keeping the overall flow, but move them to shallower water. If you can get a thermocline at, say 4 feet deep because your diffusers are in 2-1/2 or 3' of water...you have successfully reaped alot of the pond health benefits, but have not maximized the carrying capacity. This concept is really mimicking surface aeration which backs up what Mike was saying about surface vs bottom aeration.

I'm just throwing ideas around, if you can't tell.

Thanks Mike, and I certainly appreciate your thoughts QA, as well. You both bring up some great points. As this is just my second year dealing with pond stuff in general, and my first with aeration, I obviously have lots left to learn. I too, am excited about the temperature drop, but just don't know yet how much to attribute to the recent rain and how much to the switch to nighttime only aeration. Time will tell. I wish I could have some sort of surface agitation going but, again, no power close to the pond. I'll continue to monitor and will keep you posted. Thanks again everyone for all of the great advice and ideas.

You're very welcome. Keep up the good fight. It can be frustrating, but it can being very satisfying too. Feel free to keep us informed of the goings on with your pond.

Here is what I am using for shallow water aeration, it sits 30" of the bottom in 5ft of water.

Hey Shorty, I'm curious, does 30" of height still allow you to keep a thermocline? I'm 22" up, on top of milk crates and I still move water across the bottom.

The diffuser in the picture is currently sitting in 60" of water in my shallow end, the boil rocks back and forth sending waves out across the pond, the boil height bounces around from 3" to 7". To be honest I haven't taken deeper water temps to see if I have a thermocline but my deep diffuser usually only runs at night and is also sitting 30" off the bottom. My deep diffuser is also sitting in a 36" deep plastic sump pump pit with holes around the top. I only run my diffusers during the day during emergencies such as when a strong summer cold front rolls in, or more recently when chemicals get drifted onto the pond. My surface temp this morning was 69.5F, this evening it was 75F, so far this year I have only hit the low 80s for a few days.

shorty, I'm intrigued by your description of the sump pump pit and 'holes' Do you have a picture? So you have the sump pump plastic enclosure with the top on and holes are in the top (only? or in the top and sides?)

How do you keep it weighted down? And do you have extension poles holding the diffusers up 30" above the sump pump enclosure?

I have my diffuser in about 8'of water mounted about 10" off the bottom on a big plastic tote, with the height of the tote and the diffuser I'm probably 18"-20" off the bottom. I still don't know if I'm stirring up sediment or not.

I haven't run the aerator at all this year yet due to crazy amount of rain and also very cool days and nights and plenty of wind. The pond is very very clear (probably new water added and for the first time I added dye which is limiting plankton) But I do wonder if part of the clarity is that I'm not running the aerator at all.

Would love to hear the advantages of your bubbler in a sump crock idea and how you built it.

No picture of the sump pump pit, no top on it either. The idea was to try and keep the diffuser from stirring up sediment. It is a single diffuser sitting on the same style of base as then one pictured above, the base has rock in it to hold it down and is bolted to the bottom of the sump pump pit. The sump pump pit was free, no idea where it came from, it ended up in our yard after wind storm. If I had to buy something it would have been a plastic trash can. I do have an extension pole holding up the diffuser inside the pit.

Success! I wanted to wait a couple of days to make sure, but switching to a nighttime only schedule has reestablished a thermocline in my pond! I now have a 5 to 7 degree differential while maintaining acceptable DO levels. (I am running midnight to 8 AM) Yesterday evening I recorded 84 degrees on the bottom while the surface was reading 91.

Excellent! That makes a person sleep easier doesn't it?

I run my air at night and typically check my temps in the evening. My latest temps from top, 18' down, and to bottom were 87, 84, 77 F.

I don't think I actually have a thermocline by the strictest of definitions. I believe my delta T is from the water flow stopping during the day and the upper portion starting to heat back up.

I think I will try and measure temps this evening at 1 foot intervals to investigate. I thermocline should show up as a significant change in temp from one foot to the next, otherwise, I am betting my temps just gradually get warmer the closer to the surface.

Yes it does QA! Official thermocline or not, I'm just happy they now have some sort of refuge. Wish I had one out there! Been just miserably hot lately....Currently 91 with a heat index of 103, and climbing. And it's not even noon yet.

I'm glad the temps are coming around!! I know you're breathing a lot easier too!

The answer is yes! I waded out neck deep into the pond this afternoon near the shallow aerator while it was running and could feel the thermocline with my feet, it is quite a bit cooler, I'm guessing at least 5-7 degrees cooler than the water above. My shallow aerator is running 24/7 and current surface temp is 89F.

I managed to get water column temps over the weekend to share...

My pond is 10 foot deep in the middle with the deepest diffuser 2 foot off that bottom depth. The second deepest diffuser is about 6 foot below the surface and the shallow one is in 3 foot of water.

My system was operating from 9pm to 9am (nighttime only). This should allow for about 4 full turnovers a day.

Water temps were taken at 5pm. The water in 10 foot of water was 80 degrees F and remained at 80 up to the 2 foot depth. At 1 foot is was 86 and at the surface it was 89.

Even with the lowest diffuser 2 foot of the bottom, I have no thermocline. I think that the water being lifted by the diffusers is also dragging water from beneath the diffuser up with it. I still ponder on what can be done to eliminate that dragging of water so that a cooler area can be created if that is even possible in my small BOW. I am considering adding 18" to my deepest diffuser.

I have shortened my run times from 11pm to 8am as 80 degrees is a bit warm for my liking.

"Even with the lowest diffuser 2 foot of the bottom, I have no thermocline. I think that the water being lifted by the diffusers is also dragging water from beneath the diffuser up with it. I still ponder on what can be done to eliminate that dragging of water so that a cooler area can be created if that is even possible in my small BOW. I am considering adding 18" to my deepest diffuser."

I'm in the same situation QA. I think, because there is no bottom plate under my diffusers, the lift is pulling everything up from below. Even with just the one diffuser, I have less than 5 degrees difference top to bottom.

As hot as it's gotten, I've decided to shut my bottom aeration off for the summer and just run the surface fountain. Right now I've got it going 12 hours, from 4a-4p. I know the bottom will stratify and become devoid of most DO, but at least the fish will have an escape if the surface gets too hot.