stocking a pond

We are on a 60 yr old pond. We have primarily bluegills and bass. The DNR came out once aND told us a few things. Do not put in crappies. They will eat up everything and you will end up with only small hungry crappies. Catch and keep all the blue gills you catch. They need to be taken to control their numbers.If you have too many weeds put in a few sterile grass carp. We put in 8 in our 1 acre pond and they have done a wonderful job without the need for any chemicals. Ponds are great.