Don't do it! Almost everytime I've seen grass carp added to a small body of water they really hurt the bass fishery. They silt beds in the spring and destroy the eggs. During the time when bass do their thing is when these fish hit the shallows hard and do their damage. All this is my own opinion and I'm not an expert but I've seen grass carp kill several good ponds in my humble opinion. There are SAFE chemicals now that can be used. Also another alternative some people are doing is adding channel catfish. The water being clear helps to make algae grow do to the sunlight penetrating the shallows to the bottom. Channel catfish will add some turbidity to the water and inhibit the growth of the algae. Is it a cure all, NO, but it helps and it gives you something else to fish for and eat. Remember though you have to add cover for catfish to reproduce in a pond. Just some food for thought, I hate grass carp, just my two cents.