TMRC Exotics
Aquarium Advice Addict
Also have you decided what else you will be stocking? Just curious.
I don't think its stalling your cycle. I told you when you started its harder to cycle with this many fish. What I think your seeing is high amounts of ammonia being converted to nitrites while they're just not getting turned to nitrates fast enough causing you a bottle neck of nitrites. Just keep up the water changes, keep up the prime and wait on those nitrates to start raising faster ridding your trites. I also suspect a little bit of over feeding.
You will get it, best of luck.