I have an aquaponics install that is currently "fishless" in that I am in the final phases of getting it to cycle ammonia into nitrogen.  After transplanting a bunch of sickly plants started during cold weather, I was encouraged when even sickly bean plants recovered and grew thick, deep emerald green leaves.

Soon, though, I noted the same spotty yellowy mottling was coming back.  I thought this was fungus and following the advice of a local hydroponic store sprayed a $14.00 fruit…