Is this a newly set-up tank still going through a cycling period- or is it an established system? Ammonia in a new tank is expected, although it does need to be dealt with. If the aquarium has been running for an extended period of time and you're finding levels of ammonia/nitrites present, something isn't right-- i.e. overcrowding, overfeeding, inadequate filtration, etc.
Whatever the case may be, I'd suggest water changes to remove the excess build up rather than adding Ammo Lock. You'll often find "false positive" test readings when using it and you won't be able to accurately determine what is going on in your tank. Test the water after each water change until you get the levels down; just make sure not to change too much water at once.