In a new trash can with a heater, airline and powerheads...keep the heater upwards to about 84-85 degrees and scrub the rocks with a nylon brush every couple of days...after you scrub..change the about 50% of the water...when the amonia is down to 0 for a few days...then put it in your tank...I always add about a quarter of it at a time...wait a day or two, then add some more...