There are three ways to treat an acidic water. All have advantages and disadvantages. You can add polyphosphates to the water to protect the pipes and fixtures from the acidic water. That doesn’t always work.
You could use a solution feeder to inject a solution of soda ash and water into the water ahead of a retention tank large enough to give the solution time (20 minutes) to react with the acidity. They can be a nightmare to set up and maintain plus you have to keep the solution strength correct or you don’t get the job done. They take up the most space of any choice.
You could use a sacrificial mineral ‘filter’ using one or two minerals (mixed bed) that dissolve into your water buffering the acidity. That adds hardness to the water and with your pH you may expect as much as 5-8 gpg plus whatever hardness you have now. That would suggest a water softener after the acid neutralizer filter. AN filters come in two styles; upflow and backwashed downflow. I don’t like upflow because they can cause excessive pressure loss and require dumping and then replacement of the mineral if the bottom distributor becomes blocked with ‘dirt’. To prevent that you would have to install a sediment prefilter, that costs water pressure. A backwashed AN filter costs more but doesn’t have the problems that upflow can.
Quality Water Associates