I had a major winter kill in my pond the winter before last and lost everything except some bluegill and fathead minnows that somehow survived. I had a DNR fish botanist come out to determine a cause and he said that coontail combined with a lack of aeration choked out the oxygen. I need to introduce Sonar in the pond to kill the coontail. The problem is, is that with all the rain we have been getting, my overflow tube is constantly running and Sonar has to remain in the pond for I believe 30 days to become effective. And as pricey as it is, I don't want to waste my money. My question is; Can I still put in my bass and catfish before I put Sonar in. I know the Sonar won't kill the fish but I am worried that the overflow tube will continue to run all summer and I won't get it put in before winter arrives. I did install 2 aerators in the pond to keep it open during the winter so maybe the O2 depletion won't be as bad. Hoping that someone out there has been through this and can give me some advice. Also, my pond is about 3 acres. Should I put in any grass carp and if so, how many?