i have been waiting several months for my twenty gallon to cycle, about four months . I have a reading of 0.25 ammonia and 0 nitrites and nitrates. The ammonia is not rising above 0.25 even when I go a week without a water change. I tested my tap water today and I got a reading of 0.50. The ammonia in my tank is lower than the tap where the water is coming from. Could my tank be cycled?