Quarantine Help/Question

[phillybean]

I recently got a Hippo Tang and failed to Quarantine her. After 24 hours in the tank, she was covered in ich. I quickly set up a 10 gallon tank, filled it with tank water, added a sponge filter running off a Maxi Jet 400, a heater and a piece of LR. I'd dropped salinity from 1.026 to 1.021 over the past 8 hours and plan to lower it to 1.009 by the end of tomorrow.

My problem seems to be Ammonia. I was hoping that by using Rock and existing water, I would not see a cycle, however my Ammonia readings are currently at 1ppm.

What's causing the cycle?
What can be done about it?
Should I remove the rock?
If not, at what salinity should I remove it?

The fish looks to be getting better, is swimming (was on her side most of yesterday) and the ich doesn't seem as bad as it did this morning.