+1 on what RBU1 said - no controlled studies that I know of have ever been done on any "reef safe" treatment. When they work, it is just coincidental - Cryptocaryon *sometimes* goes away on its own in reef aquariums with good protein skimming.
The picture isn't really clear, but it looks like the spots are only on the fish's caudal fin? Is that correct? If so, it may not be ick - maybe broken/bruised fin rays from it being captured (although you usually only see two or three of those at a time). One trick - take a photo of the fish today and compare the location of the spots - if they are unchanging over two or three day's time, it is unlikely to be ick. If the spots come and go, and change in numbers, then it is probably ick.
Jay