I believe he or she was referring to the fact that Ammo-Lock states that it neutralizes ammonia, and Prime claims it removes it. Either of these could arrest the process, because if Prime is removing ammonia, then there's no ammonia to feed hungry bacteria, and therefore, they don't grow, and the process does not begin. This is what I'm guessing that poster was talking about. However, I have also heard many accounts of Ammo-Lock causing a false positive on ammonia tests. So, I use prime to remove chlorine/chloramine, adn don't use Ammo-Lock on anything, because I don't believe in controlling water quality with chemicals at all, anyway.