RO water vs mineral water extraction for coffee

I went from my RO filter which is basically like 1 PPM to a mineral bottled water 100-200 PPM, every bottle is slightly different in concentration. I found that I have to grind quite coarser to get the same extraction. For reference I would do a 6.0 on my K-ultra for a B75 with RO water and now I did 7.0 and it was over extracted still. I think I might go to 8.0 even which is pretty coarse. Btw if you have this lingering sourness you can't get rid of and you are using RO water....definitely try some mineral water next time.