Just to clarify re 'bad advice': the reason I was asking about humidity/timing of said humidity and leaf surface paling was, in fact, to clarify conditions and symptoms. Pm presents consistently visually but should be confirmed with a wipe test and check of daily moisture cycles. It is safer to treat potentially infected plants with precaution, maintaining what we used to call '' biosecurity" at the fish farm, not giving outside pathogens opportunity to hitch a ride on clothes. We still do not know what the %rh hits over the course of the day, an important data point; so the news of a healthy looking leaf surface after washing is good.
None of this is bad advice. It is cautious advice.