I have a customer that has a 3T FHP Open loop discharging into a creek. The water quality is not good. However, their FHP has a plugged coax 100%. I've tried flushing from the leaving to the entering and vise versa. I have also tried blowing it out with nitrogen. I could try using chemical to flush however, I don't have much faith that it will work since I'm not getting any water out at all or nitrogen. Any ideas other than replacing the coax and or unit?