Pond Boss Forums AERATION Systems questions To aerate or not ?

I have a 3/4 acre pond here I'n Wi. After checking surface water temp today Iam contemplating the deffuser.the ponds spring fed at 300 gal a hour,all year. Depth of 18ft, with average of 10 to 12. Bass, trout, gills,and perch all made the winter. Trout bit good for first few weeks after ice out. We had a few days with 70 and sunny, the surface water temp climbed to 64.8 today. And all warm water fish gills and bass were just cruising around the top foot or so of water column . It was nice to see all the fish made the winter, but has me concerned about the trout I plan on stocking I'n a few weeks.I checked the water temp of spring also today and it was 47.6.... I believe that stays pretty steady.......so do you guys think I shld even aerate or will it do more harm than good ? The trout I plan on stocking will be 12 to 14 inchers and if the bass eat a few so be it. As of the trout I'n now, do you think they just stay bottom Part of pond til they feed? Plenty of food btw, tadpoles, shiners, and you can dip net all the fat heads you want.Any input would be great guys.

Hey Jamie,

I am no expert in air but I have yet to read on this site in 4 years that if done right aeration is not the way to go it's always a positive. You have great inflow for sure but you are also 18 feet deep. That is good in winter as fish will seek deeper water then, but even if you only used the air during the winter to keep a nice hole in your pond it would be worth it I think. My grand dad had a pond in Wis. and he always had air running in it during the winter in a shallow spot to keep the ice open. I am sure some other folks will chime in and give you the exact advice your wanting, but IMO air is always a plus for your pond if (Done Right)!

Good Luck,

The fish seemed to stay on a 10 ft flat all winter. Dropped camera down plenty and never seen a fish I'n the 14 to 18 ft range. The trout were caught I'n winter at the 8 ft range.

Yeah that would tell me there is not enough D.O. down there and if they are all staying in one depth in winter they could be using a lot of D.O in that area so a winter air setup at least to keep that water flowing and making new D.O. would benifit you I think. Colder water holds more D.O. but if all or a lot of your fish are in the same depth water that could present a D.O. problem. Then if you did decide to use it in the summer you could put it in the 18 foot deep area and maybe get some of those fish to use that area too.

Thanks for the input rc51. Will the 18 ft depth stay cool I'n the summer like it does now. I'n august surface temp can be 75 for the first few feet, then I drop a thermometer to 18 ft depth it's 51 to 53 .

It may not be as cool cause you are mixing all your water but if it has no D.O. It isn't doing any good for you anyway right? So I would say your deep water may be an extra 5 to 7 degrees I suppose, but it would be mixed up good and good D.O. down there and that would be more better then colder water that you can't use!

Good Luck,

Try mixing it just enough each day to keep the bottom water below 70F or better yet 68F. Be aware that may not provide enough dissolved oxygen to keep the trout alive. Trout not only require lower temps but they also need relatively high dissolved oxygen where they are living. Minimum DO listed in the literature for trout is 5ppm (mg/L). For most other freshwater fish species the minimum DO is closer to 3mg/L.

Thanks for the advise guys, what a great site.Iam gonna maybe just arerate til bottom hits 60, I don't want to loose the trout. They made it last summer without air.Do you think 2 to 4 hours a night is enough.1/2 to 3/4 acre, most depth is 8 to 12 with a small 18 ft hole. I have a hp 120 compressor that I've had years and sinking line with rock airstone.

Hard to tell for sure?? What I would do Jamie is ease on the side of caution. Do 2 hours and then go see where your temps are down there. Then if still in a good range try 4 and then check again. If 4 is close stay there, checking it every couple of days if you can to see how it's doing. If it starts to get to warm back, back off to 2 hours.

Good Luck,

Your biggest problems and when you need to be most watchful for the deepest water will occur when the air temperatures are the highest for your weather zone, probably in July-August. At this time also your surface temps will be the warmest of the year. The process may involve quite a bit of temperature checking in the deep water. IMO I don't think a bottom water temp of 60F will provide enough DO for the trout. If the trout suffocate in the deep water I doubt you will see them when they are dead & they are not likely to float.

Once you see a pattern develop in the pond as it responds to your specific aerator system then you will have a fairly good idea what will happen in future years during the hottest part of the summer. Several members here with marginal trout ponds aerate only at night to help keep the overal pond cooler. Keep good notes of aerator run times and corresponding water temps at the surface and bottom. These data will be very helpful in the future summer seasons providing you don't make equipment changes to your aerator system. When you have a pattern developed the biggest variable will then be the affect of eutrophication on the pond which over time increases the biochemical oxygen demand of the ecosystem especially in the deepest part of the pond.

Thanks bill, i will be putting aerator I'n a week. Keep ya posted on results and temps.

Ok guys, so i don't know what Iam doing ! This weekend i let kids fish the pond, 14 gills I'n top water flies, found 4 dead today. Stress i guess. Caught 16 perch and 8 brook trout 4 ft down over 8 ft on worms . All fish CPR ... So surface temp is 63 and 45-46 at 18ft hole. I got power at pond today. Hp 80 with air rock , dropped it 18 ft hole..... Nothing no bubbles at top. I moved it over to 8 ft depth and looked great. So my question is will i be doing harm if i put it I'n 18 ft hole with No plum coming to the top of water. I will be putting I'n rainbows soon, i hope. Should i put stone I'n 8 ft to get correct plum? I won't be aerating the depths like i should be I'n the summer. Should i purchase i different defuser that will work at 18 ft depth ? Then save stone for winter use? Will aeration help with the alge bloom i have going on right now ? I need help.

I'll let the experts chime in with advice, I just can tell you what happened in my pond 2 years ago. My pond depth is about the same as yours, and I had RBT in it.

Water temps hit 70°F at the surface. Bottom temp was still in the lower 60's. The trout seemed happy. I turned on the bottom aeration system, only running it at night, or when the air temp was below 70°F. The pond started dropping due to no rain, and higher temps. Surface water temps started to climb to upper 70's. I started up the well, pumping 54°F water into the pond. Still kept with the aeration schedule. I started to notice the trout by the water going into the pond from the well. Within 2 weeks all the trout were gone. Water temps were above 70°F from top to bottom, even tho I was still only aerating when air temps were below 70°F. I can only summise that the diffuser in the deepest part of the pond mixed the whole water column (like it is supposed to) and there wasn't enough O2 in the warmer water for the trout. (no dissolved O2 readings were taken)

So, it's a combination of things that the trout need. Enough O2 to survive, and cool enough water. Just having cool water won't be enough.

But, if the trout made it thru the summer last year without aeration, then they might do the same this year.

I put defuser I'n 10 ft and will run at night, see what happens i guess ? The 12 to 18 ft will still remane cold for the trout .

So guys i took some readings today. A surface temp of 64, was very windy today .water temp of spring water entering pond 54. Water temp where kids were catching perch and trout I'n 8 fow was 54. Temp at defuser on bottom (not running) was 50... The 18 ft hole was 46......... So you guys think Iam ok running defuser 4 hours a night I'n the 10 ft range ?

First thing, if you get no surface boil from diffuser in deeper water, it is not a diffuser problem but a compressor/pump problem. It is not generating enough pressure to release air at that depth. At 18ft it takes at least 9psi.
Secondly - based on what you've told us so far, I doubt that you will get trout to survive in your pond if surface water temperatures get to 75-76F. Aeration should keep adequate DO as deep as the diffuser is located. Below that depth or maybe 1 ft below that depth there will be no DO soon after surface water is 75-76F. That is the basic thermal mixing properties of water combined with the pond's normal biochemical oxygen demand. Your pond might not be normal or typical. If the surface does not get to 75F then there may be a chance the deeper water will stay cool enough with adequate DO for trout. IMO Mixing with a diffuser cannot usually maintain bottom temps more than a 5F temperature difference and still have adequate DO for trout. As I see it, the best chance of trout survival is to aerate at the fartherest distance from the spring water inflow. Then hope the spring inflow provides enough of a cool water, thermal refuge for the trout.

Second opinions are very welcome. We will find out more on this topic in September when the water cools to below 68F and the trout if alive begin feeding again at the surface.

The trout I'n there now are alive, and surface feed. Not every day but do. Are you telling me to get larger pump Bill ? I took readings all over the pond west end 54, east end 54 , 12 ft depth where spring slides I'n pond 50, 18 ft hole 46, 12 ft hole north end 48. When i did have defuser I'n 18 ft hole,,, wow i stunk like sulfer over that spot I'n boat. Dead sea down there i bet . I should mention 1/4 of pond only get sun light for 6 hours I'n mourning. Trees shade south side of pond.

Whats the old saying? If it aint broke, dont fix it?If you have had trout survive in current conditions, I'd throw the RBT in and see what happens? Then re-assess.Sometimes charts cause us to over medicate.

Remember, as I have read on here, if aeration is not brought about gradually, noxious gases will be brought up from the depths causing toxic conditions for the fish.

Good advise James, after reading article on under aeration , I will be heading your advise.

What I am saying is your temperature-oxygen problem for trout will not occur until the surface water gets to 75-76F. Bottom aeration at these surface temps may or may not help keep trout alive. It depends. You do have spring water inflow, which in itself may naturally provide enough temperature and DO refuge for the trout depending on surface water temperatures of Jun-Jul-Aug. Your other major factor for trout survial is the amount of biochemical oxygen demand of the pond ecosystem which is determined by the eutrophic nature or status of the pond. A third factor is water clarity which determines how deep DO is produced in the water column.

Thanks bill, well i did something wrong. My crappies are dying. 3 inches of rain I'n two days, i guess they got caught I'n the water column with no o2. I have defuser over 18 ft , 8 ft down and been running it 3 hours before dawn. I made the mistake of putting it on bottom I'n 8 ft,,, not good ,,,, stird up the bottom to top. Rain for 4 days and cloudy ..... Wammo huge alge bloom. This is a learning curve Forsure. Lol..

A update guys.... Bad news for me,,, bill you were right and Iam bummed out.. Last week i went away for 6 days and came back to see most of the trout floating! Sad... I was told by a friend over this way that i stood a better Chance of not aerating pond due to bring up bottom temps... Should have listened to guy i got the trout from and you guys,,, he told me to turn on aerator and leave it on all summer.. Surface temp now is 79.. Temps I'n deep holes still at 50 to 56... Last week we had blazing temps no wind and muggy. Guess i try again this fall and run air. Man I am bummed.

Now what? On July 30 th i checked temps , surface was 80 , 10 ft flat was 70 , 12 ft holes on each end were 61-63.. And 18 ft hole was 59.. So today i was garage saleing and paid 50 bucks for a Tomas air pump, 4.2 amp don't know hp.. I plugged it I'n left it run for 6 hours I'n 18 ft hole. Went out this evening checking temps with camera, surface was 72.. And the 18 ft hole was at 71... Yep a nice pump for 50 bucks i flipped her over. As checking temps i seen 2 trout on camera I'n 8 ft at 72'.. So now do i want to move stone I'n 8 ft area and only run at night or set temp for like 65' ? Leave it I'n 18 ft hole? Run 24/7 I'n shallow water.. It sucks i think if i had this figured out i wouldn't have lost trout a month ago.. This is a record heat here I'n Wi. Just trying to get this figured out for next year. Any of you northern guys without a ton of inflow able to keep your trout this summer? Looks Like the lows for the next week are I'n the low 60's... About time.....

Any advise esshup, bill, or Cecil ?

I think i figured out part of my problem! This spring where spring creek enters into pond i hand dug a ditch. Width of 4 ft and 3 ft deep by 25 long, I'n thought of having a place for silt to settle before it entered pond. I then put straw bales along shore to prevent erosion , well they are decomposing now, they feel about 100' and around them, so i think it's jacking up temp of cooler water before it enters pond. Next year shld be different .