Trouble with adding acid is that if you have very hard water (like me) then you have to add a LOT of it. That’s (a) pricey and (b) adds quite a lot more minerals - so your calcium tends to go through the roof.
I’ve used AML (CRS) with some success, but on the whole I reckon it’s easier and cheaper to get a cheap (aquarium type) RO filter for about £40 and accept that it takes a while to collect the water. If you like you can uprate the membrane and restrictor and/or fit a booster pump to increase the collection rate. Bypass water goes on the garden
Spotless water etc seems like a good option but personally I prefer to make my own