Are you saying your nitrItes spiked after dosing ammonia up to 4ppm and then your ammonia fell...isn't that a good thing?
During my cycle, my nitrItes were always reaaaaly high. So high I couldn't measure them. But my ammonia kept dropping to 0 every time I dosed it up. As a PP suggested, I did a lot of 50% PWC
to get my nirtrItes to a readable level. My nitrAtes stood around 20ppm the whole entire time. But I have a few live plants so I'm not sure if that made a differnece. I gave it a couple weeks and sure enough, it all started balancing to 0 while my trAtes jumped to about 40. I do think my cycle stalled at some point and did a PWC
and added some ground up fish food to add some nutrients back to the water as the FAQ in my siggie suggested. I think it worked.
Anyways. I didn't do a cycle with the shrimp so I'm sorry I can't give you specific help.
That's wierd your Ace didn't have any ammonia. My ace is in a po-dunk town and they still had it.