Originally Posted by joe&rae
i did add rock but it was not live and i have not added anything else but i did change the tank ...
You changed the tank? You mean you transferred everything from one tank to a different one?
If the rock wasn't cured, then that alone probably would cause a mini cycle. But if you actually switched to a different tank, and moved the sand bed with it, then that will cause a cycle also. When switching tanks, it's best to leave the old sand alone so that you won't stir up all the nasty stuff thats buried down deep.