Set up a 20 gallon with live sand, mostly dry rock and one piece of live rock. Tested after 6 days, ammonia was 0.5 ppm, nitrite was 0.5 ppm and nitrate was 0 ppm. On day 7 tested and ammonia was 0.25 ppm, nitrite was 0.25 and nitrate was 5 ppm. Could it be possibly that my tank is finishing it's cycle already?