It's a dreaded issue for cloth diaperers - "How do I get rid of these stinky night time diapers?"
My experience relates to my youngest son who was only wearing diapers at night. I was down to one in diapers, and only had a few in the pail at any given time. The amount of pee, plus the wait between washes was doing a number on my nostrils with the ammonia smell. The diapers were starting to even smell immediately after he wet in them.This can often lead to rashes or ammonia burns too.
Here's what I discovered: The ammonia comes from the bacteria that grows from the urine. The urine itself doesn't have ammonia in it. This meant I had to take care of a few things to get rid of the problem:
1. Rinse out and/or soak each night diaper in the morning (toilet, diaper sprayer, bathtub, sink, etc.). This gets the bulk of the urine out so it doesn't continue to sit and breed bacteria.
2. Add a splash or two of vinegar* to that morning rinse/soak for really smelly diapers (don't do this if you have hard water, it will make it worse I heard). Once I started this, my diapers rarely smelled right away in the morning.
3. Wash every 3 days, even without a full load. Any longer and it was asking for disaster. I set my washer to the low water level setting.
4. Use HOT water.
5. Use plenty of detergent. So many diapering resources say not to use too much detergent to avoid buildup and repellancy issues, however, if you have stinky diapers, they are not CLEAN and you need more! (use an extra rinse, if necessary)
6. Use plenty of agitation - use the heaviest wash setting.
7. Do a full double wash, if necessary.
When the urine dries inside the diaper, it crystalizes. This makes it harder to remove from the diaper. You have to break this down with lots of water, agitation, and detergent. Certain fabrics retain it more than others, such as microfiber or thick layered diapers. Natural fabrics seem easier to keep clean when stink becomes a problem - cotton prefolds or bamboo might do the trick.
Do you have any tried and true solutions to night time stink? I have heard many people swear by soaking their diapers in Rock'n Green detergent, though I haven't tried it myself.
*Some resources state that vinegar can deteriorate elastic in diapers. I never personally found this to be the case.