I use this whole house water filter to pre-treat all my brewing water. It removes chlorine from my tap water.
I used to boil my water a day before brewing. This did two things, first it boiled off the chlorine and second it precipitated the bicarbonates. Bicarbonates are undesired in beer. After the boil you let the water cool and the bicarbonates fall to the bottom of the tun. This reduces the alkalinity (lowers the pH) of the water.
Since I boiled in the liquor tun, I'd need to rack this water off the precipitate into another vessel. (If you don't it will recombine with CO2 in the air and go back into solution.) Then the precipitate needs to be removed from the liquor tun. Then, finally, it is racked back to the liquor tun. Whewwww.
Well, now I just run it through this filter and adjust the sparge pH with lactic acid. Not perfect, but it saves a lot of time and propane. In side by side tastings we could not detect a difference. I'm sure it depends on the chemistry of your water.