i bought a large 12 pound pukani rock from brs and i have had it in a tub for about 3 weeks.there are 2 powerheads and a heater in the tub. i have done at least 3 water changes and it still has the same cycling rock smell to it. my question is if the water needs to breath, i have had it covered the whole time with a lid. i have cycled dry rock before with no lid and it has never taken this long.