Found this article on high ammonia levels, here's the link Handling High Ammonia Levels
This is pretty informative, I think. I have heard several times that salt can kill the beneficial bacteria in the filter, but have yet to confirm this. If the salt does do this, it's possible when you treated for ich, that is what happened. Especially if you treated for ich very soon after the tank was set up and it had not had the chance to get cycled.
Your nitrates (the ending result of the cycle) are dangerous to your fish over 40, so 20-40 is ok, but to strive for 0-20 is even better. Anything over 40 is a definite cause for concern and must be resolved soon before they get higher.
Hope this helps some. My goodness you are up late :) It's midnight here in Nashville, TN not sure where you are but hope you can get some sleep and not worry too much. You are doing everything you can, we all have to go through these steps, but you've had fish tanks before, you can do this!!