Koi

How much at the moment should i feed 11 koi and 2 goldfish. Consist of 2, 18" koi , the rest between 6 & 12. I think im overfeeding , any advice . 5500 l pond . Its now just getting a bit cloudy after a week and a half. Running oase 18000 , plus smaller pontec 8000. Uvs working ok. Ive been feeding about 4 times a day as they seemed to clear it. Probably too much?