You want to keep adding something (fish food, shrimp, ammonia) each day so the ammonia readings stay at 3 ppmish. So, for example, say you find that adding 3 drops of ammonia gives you a reading of 3ppm. You keep adding 3 drops of ammonia/day knowing that it gets you 3ppm. Test it each day. When you see that your 3 drops of ammonia no longer registers on the ammonia test (you get a 0) and that the nitrItes no longer register (you get a 0 because the bacteria is breaking it down to nitrAtes immediately), you will have a nitrAte reading of 10ish or more, and that is when you know it is done. I have not used the shrimp method, so I am not sure how you would go about monitoring that (i.e. not addig daily drops), but I would say add another shrimp, but probably only half of what you used, so your Ammonia does not exceed 5ppm, and when that registers 0, and nitrItes are 0, and nitrAtes are 5ish +, you should be good.