Check out diaper jungles detergent chart like the pp stated. Personally, since you have softer water, I'd recommend Charlies or Tiny Bubbles. Charlies is an awesome detergent, that works best in softer water, there has been some problems with severe rash when used in hard water. Its super cheap when purchased in bulk and great for all your laundry so you only have one detergent to use.
I use tiny bubbles too, it is my favorite for diapers but I have harder water, so I'm scared to use the charlies too often. But I do use it on my diapers when I have some pretty hard core poo stains on them and magically the charlies takes it away.