Hard water help

[Pootklopp]

Hello all,

I'm looking to solve my hard water at my house. I have tested using this and believe the "general hardness" test works for measuring my grains (21). I (3 family members) am on City water and used 80,000 gallons in the past 12 months.

I had a local plumbing company quote an install and was given Lancaster Model 7 PEL-150 as the recommendation from them.

Could anyone give me any feedback on if my testing method is correct and the recommended softener?

Thanks!