Hello, I have a 3/4 acre x 6' ave. depth pond that I have successfully controlled FA in for the last 5 years using CUSo4 dissoved in H20. I would spray it on surface of mats treating about 1/2 the pond edge at a time. Last fall I put in 10-12" to 14" grass carp to try and solve my underwater weed problems. I haven't used any cuso4 since I put the carp in and my FA is taking over this spring (1/2 the pond surface). My question is can I still use CuSo4 or Cutrine at any level to control the FA. or is any level poisonous to grass carp. Any advise or dosing rates would be greatly appreciated. Thank you very mcuh