Hello gcdj and Welcome to Fish Lore.
It sounds like your tank is experiencing a bacterial bloom which is very common in new tanks up to 1 year. I really don't think your java moss has anything to do with your current problems. If anything the moss will help.
Anytime you remove bio media from your tank or filter you are risking a mini cycle which is what your tank is experiencing with increased ammonia levels. Since your good bio media was rinsed under tap water, assuming you have chlorinated city water, it more than likely destroyed the good bacteria the tank needs to process the ammonia.
I would suggest daily 30 to 50% water changes. Add some Prime or Amquel + (or conditioner of your choice) to detox the ammonia for a 24 hour period until it's time for the next water change. The main concern now is getting the ammonia levels to 0 as the bloom will go away with water changes and once it has run its course.
Once you have 0 ammonia, 0 nitrites and under 20 nitrates you have regained your cycle.
Continue to feed your fish

Just don't "over feed".
The
test kit most recommended on this site is the API (liquid) Master Test Kit.
Best wishes!
Ken