Water
Hardness numbers you can act on
gpg, ppm, and what to do after you test—before you buy a system. Clear metrics without the sales pitch.
Hardness ranges (gpg)
Soft 0 – 1 gpg
Slightly hard 1 – 3.5 gpg
Mod. hard 3.5 – 7 gpg
Hard 7 – 10.5 gpg
Very hard 10.5+ gpg