i just recently got a 29 gallon tank with a very recently used filter and used gravel. I have had the water cycling for three days now and have measured the PH at 8 and the ammonia and nitrite at 0. If i want to use fish to help move the cycle along when should i add them? (i do not have to buy any fish because i have about a dozen baby mollies in my roomates tank). Also should I try and drop a PH a little?