I thought this had got better but it's got worse again - his nappies (flexitots) come out of the wash smelling completely clean, then after a couple of hours on they often smell of ammonia. And if I put a reusable on him at night, the smel in the morning is like opening a bottle of neat ammonia.
I do a short cold rinse before washing, have switched from washing at 40 to usually washing at 60, and put 1 1/2 tbsp of vinegar in the fabric conditioner drawer.
Any ideas gratefully received!