48hr post startup and i'm at 0.70. I haven't ruled out coring out the concrete slab a foot over from the pipe and creating a sealed off hole that the pump can suck from, but i do wonder how much better I can get from 0.70 for the added expense and price.
My friend has a sealed off system professionally installed and he hasn't gotten below 1.5. However, my office is in the basement and I spend a lot of time there, radon is a very real concern for me. If I can get to 0 or even 0.35 that's even better.