Marine Ich lives mostly in the gills and can not be seen. When you see the white spots its due to the spreading of the ich, not the start. Loss of spots means the Ich has retreated, not that its gone. Life cycle of Marine Ich is 60-90 days with special cases up to 120days.
There was a post I put up about a month ago copied from another website with lots of good information on it about Marine Ich. About the only thing that cures Marine Ich is copper and time, garlic helps though.
http://www.reefsanctuary.com/forums/...ths-facts.html
Good luck