I went through this same thing, nitrites refused to budge for a while. (They're gone now... I may or may not have done a silly dance when that happened) I don't think water change will help, but I think you could try what roadmaster suggested... Just decrease your ammonia dosing a little, and see if they can handle that in 12-24h. I stopped trying to dose to 2ppm every 12hrs, and just did it every 24hrs and they seemed to "catch up" after that.
If you're worried about a big bioload at fish time, once you know you have the right nitrIte to nitrAte bacteria present, I imagine you could gradually beef them up by *slightly* increasing your ammonia dosing over several more days.
Disclaimer: first time cycler, hopefully I have it right! Others will likely chime in to help as well... Gotta love this forum.
I bet you're in the same zone where I was though, thinking it was never gonna happen, and then it did.
Last edited by Pika; 02-18-2014 at 12:10 PM.
Reason: Newbie offering advice disclaimer!