Hi Mike,
I'm a noob myself so take anything I write cautiously.
I'm also battling ammonia in my tap water. In my case though it is 1.0.
Regarding test kits, I'm using an API Master Freshwater Test Kit. I didn't know it when I bought it but it's ammonia test is a two part salicylate (hope I spelled that right) test. The significance is some tests apparently read ammonium as ammonia. I've been told that the two part salicylate test reads ammonia only.
I seem to be having good luck with API's Stress Coat + as a water conditioner/ammonia reducer. (I suspect it has liquid Ammolock in it as the label states it treats ammonia.) A teaspoon per 5 gal of tap water reduced my 1.0 to .25. The LFS said I could double up the dosage if I needed more reduction. As it appears to be a good shop, which the owners work in, I took them at their word and put in another teaspoon. After a 25% water change last night, the fish seem happy. (They showed stress after prior water changes, so I stopped until I could try something different.)
I won't be able to test the water until after work tonight.
I'll look for the Prime. It sound like you and others have good results with that.
Hope this helps and good luck.
Greg
in KC, MO