You certainly convinced me, and I admit I was skeptical!
In in the freshwater flush line to my watermaker I had added a carbon block filter to the fresh water feed line to remove any last traces of chorine from dock water that might be in the tank, so I already have one ball valve in line to isolate that from the pressure water system, and the previous owner had already installed another ball valve just before the Dessalator three way valve. That makes two...
If I keep them all shut during normal operation, I expect to never see the problem...
---In amelyachtowners@..., <sailor63109@...> wrote :
It was most definitely the flush valve at the watermaker pre-filter. I verified it this way: