Ive been cycleing with shrimp. The ammo got up to four and i tested nitrite about a week and a half ago. And for the past week the ammo has been 6+ppm. I have been to busy to change it. Now i did a pwc and its down to 2-3 and no nitrites. I didnt test before i did the pwc but am i cycled or did i kill the nitrite with the amount of ammo?