Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Copper Sulfate and Grass Carp Kill

I have a 50 year old three acre aireated pond. It is about 18 ft. deep in the deepest. The aireation system has been in place since mid-year last year and until about two weeks ago was doing a great job of controlling the FA. Two weeks ago FA just seemed to appear overnight and there was enough of it, and about 15% cover of Duck Weed that last Saturday I spread 50# of Copper Sulfate (this is the amount I have used several times in the past). I trailed a gunny sack in the water and made one complete circle of the pond and felt I got a fairly even distribution.

Surface water temperatore is 78 to 80 degrees.

Yesterday afternoon a found a 24# grass carp dead. Another one this AM. Looks like I messed up big time. I am not overly concerned about the grass carp (I stocked 11 of them about 5 years ago and I have never been convinced they helped any), however I am quite concerned about other species, especially Blue Gill and Bass.

The good news, I hope, is that yesterday AM I caught a 1# bass and last night I caught 5 more between 1.5 and 3#. They were very active in shallow water in the shallow part of the pond where I found the first dead carp. Since I have a relative who is restocking I held the morning catch and combined it with the five in the evening and he picked them up last night. I tell this part because the bass were active last night and one bass did well in my rabbit hutch cage in 5 ft. of water all day. I view this as a hopeful sign.

Did I poison the Carp, or create a low oxygen level? The dead carp were found in separate coves in the shallow end of the pond.

Any ideas, specifically I am interested in knowing if there is any course of action I can take to minimize the problem. I am running the aireators about 12 hours a day. If the problem is DO will this help? Should I run them full time?

I have four shallow diffusers and one in deep water. I have shut off the deep end one, thinking originally that it would keep the Copper Sulfate in shallower water, and now thinking that bringing up the deepest water will not be particularly helpful if indeed I have a DO problem.

Any suggestions would be appreciated

Bing