Sharkie

Used Paracleanse on a koi tank at work (had visible external parasites and suspected internal parasites). Next day, the tank was very cloudy and ammonia was at 1ppm. For three days now, I have been doing 50% water changes. Ammonia is still at 1ppm. Two koi died. I have them in another tank for now, but I am not sure what to do tomorrow. Maybe a 75% water change and large ammonia filter pads? We'll see how it goes.