Has anyone had good experiences with a saltless water softener/conditioner in their home?

I live in an area with hard water, at about 400ppm. I have a salt water softener already, but am tired of having to fill it with salt that just ends up in my septic system, and ultimately into the ground water.

Most advice says you can’t soften water without salt. But I’ve had good experience with ProOne’s gravity water filter, and noticed they also have a water softener/conditioner. Unfortunately I can’t find much info or reviews on their saltless softener: https://prooneusa.com/product/prosoft-saltless-water-softener-conditioner/