I have a 1 acre pond that will be 2 years old in October. I stocked it last Spring. (FH/CNBG/LMB) I just installed a Kasco 3 diffuser system this past weekend. Day 1, 30 min, Day 2, 1 hour, Day 3, 2 hours and today, 4 hours. Since then, I have had about 5 or 6 of my biggest BG float. I checked each one and none had any visible sign of injury by GBH, cormorant, etc., so I am assuming that they died as a result of toxic conditions caused by the startup. Granted, in the grand scheme of things, 5-6 fish are no big deal, however, I am curious if others have experienced the same when starting up. Should I continue with the "double it everyday plan," or should I slow it up some?
Thanks.

I would back up to at least an hour a day, run that schedule for a couple of days. If you can get down wind of the aeration boil while it's running, use your nose to tell you what's going on. If you detect a strong smell of pond, back off more until you no longer smell the odor. Then start adding time again. If you start smelling those gases again, hold at that time until you no longer detect it, then add again.

Edit: Mike beat me too it, but he is talking along similar lines as I am...

I did not have this problem when starting up. I did start out at 15 minutes and doubled from there, but others have reported situations similar to yours. A pond that young should not have any appreciable toxins, however, it's possible that the DO got thinned out to quickly.

Make sure you do not smell any sewer-like fumes during runtime which a young pond is not likely to have. I have little real experience as my aeration system is only one year old, but I would back off increasing the times, maybe even back up to two hours and stay there while monitoring for more floaters. If no more floaters after a a day or two start increasing the runtimes, but at a more gradual increase rate.

My 2 acre pond was only 2 years old and I smelled gassy sewer rotton egg smell when I turned my Kasco and 3 diffusers on for the first time.I don't even get leaves blown in my pond to docompose but the smells were there. 15 minutes a day for several days. Then 30 minutes a day for several days...45 min,1 hour,etc...each time I could still smell rotton smell but it finally cleared up and I had thousands of fish in there and never lost a single one. My advise is just be patient,go slow with it and you should be fine. Good luck. Let us know how it goes!!

My set up is similar in pond size numbers of diffusers. Rotten egg smells downwind too. No mortality at start up though.
Start up for me differed in the way I introduced the diffusers. Only one at a time, weeks apart before adding the next into the equation.

Three at once sounds like a bit much, even when monitoring time lengths.

UPDATE:
I finally finished my startup and have been running 24 hours straight for the last full day. Haven't seen a floater in 2 days so it looks like the dying is over, thank goodness. I ended up losing about 25-30 of my largest BG but nothing else. I can only assume that maybe they were more susceptible due to spawning stress. I had no idea that in such a new pond, and with such little leaf litter etc., that the bottom water could become so toxic so fast. Now everything is getting back to normal , however, the aeration has really muddied it up. I'm hoping that gets better soon.

Turbidity from aeration isnt uncommon. It should start clearing up in a couple of weeks or so.

My Kasco diffusers (6) always kicked up dirt of the pond bottom. And after I herd Bob Lusk say it's not good for the fish or the pond. I tried setting the diffusers on cinder blocks and plastic type baby swimming pools on the bottom where I set the diffusers. None of that worked. So I then built some metal tables that were 21" tall and set the diffusers on the tables. That worked! And it also let some cooler water stay on the ponds bottom which gave some place for the fish to cool off a bit during the hottest time of the year. All of this was a learning curve for me so I thought I would pass it along. And one more thing I learned is running 24 hrs per day here in the south will cause the water to heat up too much so now I just run them for 10 hrs during the night.

A plastic milk crate works well for keeping the diffuser off the bottom too.

I have my diffuser sitting two milk crates high without the bottom plate. It still pulls up some detritus initially but it settles after a couple of weeks. I also have no thermocline and only about 6 degrees difference from top to bottom, so monitoring surface temps is imperative to prevent super heating the pond. I only run at night/early morning now, 12 hours for now, but that schedule will be adjusted to shorter runs. I get 4 turnovers in 12 hours so I can afford to run shorter times.

Hmm..Sounds like I may have to adjust my diffusers if things don't settle down. Thanks for the info guys. Now, about superheating...At what point should I switch to nighttime only? What temperature gradient am I looking for that will say it's time?

The first thing you may want to do is get some temperature readings from different depths. A pool thermometer with an adjustable weight works fine. Try to determine whether you are still keeping a thermocline and at what depth it is. It will be that level where there is the biggest change in temp.

From a water temp perspective, if you are maintaining a thermocline, you may not have to go to a nighttime schedule, depending on what depth it is and how much cool water is available. Theoretically, it should be the depth of your diffuser. If you are mixing water from top to bottom the variance will be very small, maybe 3 or 4 degrees. If that is the case, like on my pond, I shift to nights when my surface temp started teasing 80* farenheit.

Now, my pond is small, sees no wave activity from wind and is completely shaded by 7pm. If your pond is getting a good wind stir, that will have an affect on surface temps as well.

However, regardless of surface temps, you will want to set up a run schedule from around 2am until around 8am. This is the time period when your pond will have the lowest DO, which is caused from respiratory activity from dying algae and your fish using up the oxygen.

I am learning my pond as it is only the second year with air and plan to gradually shift from it's current schedule of 7am to 2pm as the temps tease that 80 degrees that Mike mentions. I will start to shift the schedule back by an hour or two at a time until I get to 9/10pm to 7/8am.

Last year when I switched more abruptly, the fish's feeding of pellets turned off and it took several days to start back up. We'll see if this gradual approach works better as my water is well into the 70's and the move to night time air is quickly approaching.

As far as the aeration system muddying the water...I only ran one shallow diffuser during the winter for a couple hours a day and between that one diffuser and plenty of inflow, the pond stayed muddy with only 12 inches of clarity (secchi disk reading). Now that I have been running 7 hours a day and the inflow has backed off, the pond's clarity is up to 18 inches. This 6 inches of improvement has come about in just the last week or so. My three diffusers are about 20 inches off the bottom with no substantial base plate. I don't know what conclusions to make at this point, but inflow definitely muddies it up and the diffusers seem to keep it stirred up until the inflow stops.

Well, guys, I am one week in with aeration and I have to say that so far, it hasn't been very nice. Even though I thought I was starting it off super slow, I obviously wasn't slow enough because I lost about 25 of my biggest BG and did who knows what damage to this year's spawn. I know things will settle down and improve eventually, but right now, my pond looks the worst it ever has. The water is super muddy and covered with a bubbly scum like I used to see in my marine aquarium protein skimmer. Overall, it just looks terrible. I just had gall bladder surgery so I haven't had a chance yet to go in the boat and check the temps, but I will as soon as I can. I guess I just wasn't prepared for the big initial negative changes, but I'm hopeful that things improve soon. Just sort of depressing right now.

Ok, Three weeks in now. Water looking better but still not great. Fish are still feeding good so no change there. No more fish kills since the original 30 or so. I just made a slow "troll" throughout pond dragging my Oxygen/temp sensor and my DO level is consistent throughout the water column ranging from a low of 6.0 to about 7.7 at the surface. Temps are now also consistent and range from 89 at the surface to 87.5 on the bottom. I realize that the temps are only going to get higher so I am wondering what the limit is. I would prefer to continue to run 24/7 but I'm not sure where the temp cutoff should be. Thoughts?

I don't know much about the DO level readings...wish you were my neighbor and we'd survey my pond too.

Your temps from top to bottom tell the tale that the aeration is turning the pond over well, but I avoid getting that warm. I try to get my aeration running only at night about the time my pond is in the low eighties. That time is quickly approaching here. I have read that there are not regular issues into the 90s, but most want to stay below 85 if they can help it.

Good to hear that you have had no more floaters!

JKS...before I put in aeration, I had surface temps hitting 99f. It didnt appear to affect the fish, and they fed very well. However, without aeration, I'm certain there were much cooler temps deeper that they could escape to. The problem when water reaches those temps is it cant hold the DO they need and the deeper water, even tho cooler was being depleted of O2 as well. I think it was just a matter of time before the pond crashed and I had a big die off.

It takes time for things to settle out, but with your DO readings, your getting a good mix top to bottom.

How warm is too warm? Your guess is as good as mine and only the fish can say, but when that happens...its too late. I dont think your smaller fish were affected, since you didn't find any floating. The bigger fish are always the first affected, since they require more oxygen.

I know your frustrations, as I have them too. Aeration tends to stir up the bottom and can make the surface look bad at first. And when it gets hot, and you should cut back on run duration, the stirred up nutrients create algae blooms near the surface. It's hard to be patient and let things settle, especially when you're looking at it every day.

Glad to hear you're on the mend!!

Thanks Quarter Acre and Mike, I truly appreciate your input. I guess I am going to see what happens. Until I see a fish kill I think I am going to forge ahead with my 24/7 schedule. I have another .6 acre pond that is only about 5 ft. deep (avg) (not aerated) and I know the temps get quite high in it each summer, yet never had a fish kill. Being only 5 ft' deep, there can't be much of a thermocline and I imagine its all pretty hot top to bottom each summer. With that in mind, I'm thinking that there is a pretty good temp tolerance in the local adapted population so I am going to continue to aerate in order to distribute DO. I'll monitor and, of course, if I see problems I'll change my plan. What do y'all think?

You never know until you try, bud. It's a learning curve we all have to put ourselves thru and hopefully by passing on the experience, we all learn from it. One thing is for certain, no two ponds are the same and they all respond differently.

Since you have a D0 monitor, you could start backing the aeration off during the hottest part of the day and keep track of the D0. Keep increasing the down time of the air until you see the D0 dip near unfavorable levels and balance it from there. This could maximize the D0 while minimizing the temps.

I have not studied about proper D0 levels, but, in my novice mind, you really don't need to run the air any more than required to keep the D0 up. I bet that your aeration system has some extra capacity and may not need to be run 24/7. There's that "learning curve" Mike referred too.

I don't think continuing until you see a fish kill is a good idea when you have the tools and hopefully the hobby time to foresee a D0 problem.

And please...keep us amateurs informed on your progress. We would all appreciate the information.

Probably a much better idea than my "full speed ahead" approach. lol
I think I'll do as you suggested. Thanks

Oh please Mike, what little I know, and it's only a little at this point, I have learned from those of you here that are much wiser pondmeisters than myself! I still consider my self in the big dummy phase.

Thanks, but I'm by no means a "ponsmeister"!!

Everyone sees things differently and those observations sometime generate discussion that can possibly enlighten even the most experienced. What may seem trivial might be of interest. We're all learning something every day.