I have a nitrite spike, but water changes aren't doing anything?

I've had bad luck with fertilizer in my aquariums. like the other person said (sry I couldn't remember your name) if you have access to any other items from a cycled tank (decorations, substrate, filter media) then you can add that to your tank. I'd just do a 30% water change daily until you get your water parameters back to where you want them.