, in and of itself, will not fix an algae problem. You need proper fertilizer dosing for your plant load, proper lighting and a proper PWC
As far as using and setting your pH controller... Set everything up and START SLOW. Use your drop checker to gauge your CO2
(and watch your fish closely) and turn the controller down a tiny bit at a time until you reach the desired color in your drop checker. Then after about a week or so of tweaking the system you can pretty much just forget about it.