I am an aquaponic farmer in NE Pennsylvania that has just started experiencing 100% fish mortalitiy, TWICE. I would like top talk through someone with more experience before I completely drain and sanitize my whole system. If that is a possibility, I would really, really appreciate it. This is not an ammonia or nitrite spike kind of issue. Those metrics are fine 0.25 and 0 respectively. DO is 6.4 ppm and pH is about 8, which I know is a little high but hardly enough to cause a problem especially seeing that ammonia is not spiking even on warmer days.