Yes it is an important step in areas with acid soils ( pine lands , many swamp type settings) - much but not all of the SE US.

If the FA is limited in amount and just around the edge you may be able to rake it out or used hydrated lime to kill it. Care must be taken using hydrated lime as it rapidly raises the pH to the lethal range for fish and plants but it does increase alkalinity for a short time (weeks). Used in small amounts at the edge it will kill FA and not kill many fish if applied directly on the FA after first making the fish swim away from the area. Copper products can also be used to spot treat FA.