Review on Seachem AmGuard 500ml Aquarium Water Treatment by Melissa Wilson

I have a serious ammonia problem - in fact I have removed everything from the tank including the fish and substrate and cleaned the substrate and everything in the tank. The fish was in a 5 gallon bucket with an air stone. I was hoping to get rid of all the dirt in the substrate, get rid of hundreds of snails and lower the ammonia from a dangerously high 2ppm. It took over 5 hours. Before adding the fish I measured the ammonia level and it showed 1.0ppm - how can that be? I added Amguard before putting the fish back in the tank and it didn't affect the ppm. All my fish are alive despite very high levels of ammonia. It makes no sense. I was going to try this with my other two tanks, but what's the point if AmGuard doesn't remove the ammonia?