Hello all, first post here. I just got a house that has a Kinetico Water softener and RO system installed. The softener has a label that says "Softener-50" on top. It's two tanks, about 20" tall and a box with salt in it. It had been on "bypass" and I switched it to run through the system to see if it worked. When I went inside and used the water, the water ran a yellow-green color and sandy. I realized through some other searches that this is probably the resin media from the system. Couple of questions:

1) is that resin stuff harmful to the plumbing (other than clogging the screens on the faucets)

2) What would cause that resin to come out in the first place? I assume something has broken.

3) How much would that thing that broke cost to fix and where would I get parts if I can do it myself (I'm handy) (Phx, AZ area)

THANK you in advance for any help!!