Right now, the radon appears to be very "localized", to a single sump hole.
And, I do use a Dehumidifier down there during the summer.
Yeah, maybe I should go ahead and install a new
"FanTech 4" Radon Mitigation Fan" in some 4" duct work (PVC pipe?),
but install the fan indoors, about 4 feet above the sump.
I can always work on the other health hazards next year..
That might be a good way to go. I'll just have to install a check valve
in the 1.25" sump (water) pipe, to keep air from going backwards
and flowing out the bottom(water intake) of the sump pump..
And get a air good seal around the top of the hole.