Draining softener into a sealed sump pit | Terry Love Plumbing Advice & Remodel DIY & Professional Forum

I would like to add a water softener to my house, but my sump pit is sealed for a radon system. If I wanted the softener to drain to this sump pit, how could this be accomplished without breaking the seal? I was thinking I could add a standpipe with a trap, but I'm not sure if the trap would be sucked out over time by the radon fan. There is a separate sump pit for a floor drain but that drains to the septic, and I fear the brine will degrade the concrete septic tank. Any ideas?