Ok, reading some threads and getting a little worried. My 60 gallon tank was set up a week ago with 60 pounds of live rock(cured) 60 pounds of live sand. I have an excellent skimmer and filter. My numbers are perfect. No ammonia no nitrite and a reading of 5 on my nitrate test. The thing is I've never had any type of read for ammonia. I have 4 Chromis to start and still no ammonia. So I added a clownfish. Again great numbers. Is this possible or am I in for a big surprise?