I don,t know but I would have thought the ammonia reacting with the water would raise the pH by the production of hydroxyl ions. If it locks up ammonia I would have thought it would lock it up tighter than that. I don't know, I have never used it and have no idea how it works, just curious. I am an old fuddy that avoids these additives and and tries to do things that will not produce an ammonia spike.