Yeah I haven't really seen anything 100% conclusive saying that any bottled product can safely replace a proper tank cycling.
OP you should monitor your water parameters carefully. I'm assuming what you're seeing here is a bad ammonia or nitrite spike. Forget the instructions on the dumb API stuff. Do a large water change ASAP and check your water parameters or your other fish will probably be dead soon. If possible, secure some cycled media from someone and have all your filters on. When you clean a filter sponge all you want to be doing is squeezing it out in tank water or dechlorinated tap water otherwise it kills all the bacteria in the filter.