My tank has 20 pounds of rock, 1 bag of black live sand, and i used a bottle of bio-spira. My ammonia is at 0, my ph is at 8.0, nitrite is at .50 and nitrate is at 0. I have 1 live peppermint shrimp in it. Yes I know I shouldn't have a shrimp in it but it's to late. My question is why don't I...