I am aware that it is not good to do that, however I am also aware that many people do it without problems. I have a 30 gallon tank, and it has been established for two years. My ph level is 7.6, and ammonia is 0 ppm (or very close to) , nitrate is very low as well. I am aware that I just have to monitor the tank for an ammonia spike but I am not going to be extremely concerned about it. I have added about 15 fish within 5 days, all small fish (between 1-2 in. maximum adult size)
ammonia levels ARE at zero as will as nitrate levels
ammonia levels ARE at zero and Nitrate levels as well, my filter is rated for a 55 gallon aquarium with a bio wheel