Ammo lock will convert the ammonia to ammonium which is normally non toxic. However at a level of 8 ppm
(hopefully that is the total ammonia and ammonium level, not the remaining ammonia level) it may still be harmful. The future problem is once the bacteria convert the ammonium to nitrites, it is as harmful to fish and cannot be "locked" like ammonia can. keep a close eye on trites once they start to show and water change often.
What test do you use for ammonia, as that should determine if your 8ppm is just ammonia or the combined total, ammonia and ammonium.