if you took out ALL of the filters in your power filter then you probably threw away a good percentage of the bacteria that breaks that stuff down. you should only change part, or in your case half at a time to preserve some of the bacteria. also, the live rock probably needed to be cured also which means that it will cause an ammonia spike which then means a spike in nitrite/nitrates too. in a couple weeks you will probably be ok again, but for the future don't change all your filters at once and cure the live rock before putting it in the tank. both will affect your levels, unfortunatly you did it all at once!
Figuring out how to keep my fish healthy is like the pethagorean theorem; there is no solution.