Wash routine/detergent help!

I’ve been using cloth diapers for about 2 months now. I had been doing a short full cycle on cold for prewash with a small amount of detergent and then a heavy duty cycle on warm with full detergent. Both on large settings. The diapers come out with a certain scent. Not terrible and not ammonia but not good either. But after drying either in the dryer or line dry they are fine once completely dry. I can sometimes smell it though in my baby’s room. So I obviously have to improve the routine somehow. I had been using All Free and clear but I just read on fluff love that it’s not recommended. What should I do to help my routine and what detergent should I try?? I definitely need something hypoallergenic!