My tank has been up for 4 weeks now. During that time I have seen my Ammonia spike as well as my nitrite. Got some diatoms to show up on Sunday so went and got a partial clean up crew. I will add more later as I want to make sure there is enough for them too eat. My Ammonia is at 0 as well as nitrite and nitrate is at 20ppm. Do you all feel that it is safe to add a few fish this weekend or should I wait another week or 2.