No experience with API reagent test kits for ammonia but notice many report an issue using that for ammonia and what I’ve used for cycling or when suspecting a fish loss is the strip. Have tested this against a reference source and it was correct. See it go to 3 ppm then back to zero. Seachem has an ammonia alert that goes inside the tank which only test free ammonia. Since this is temporary. The API strip good enough. End up throwing it out because they expire and I rarely use them.