Hi, and welcome again, sadly there is no treat for Marine Ich (Crypto crayon) which is reef safe.
The steps you need to follow would be,
1. Establish a Quarantine tank ASAP. (This tank only needs to be equipped with heater, pvc for hiding places and a filter sponge), you can use display tank water as fish are already contaminated.
2. Remove fish from main display and place them in QT
3. There are only two proven methods that work against Ich, Copper treatment and Hyposalinity, both have to be applied by the book. In case of the copper treatment I would recommend Seachem Cupramine which maybe is the best copper treatment, of course, both of these treatments can only be used within the QT and not display tank as you would kill corals, live rock and sand and inverts.
We have a top marine doctor in the forum (Leebca), check out this link, lots of sticikes to read with unvaluable information,
Fish Diseases & Treatments
Once you begin treatment, even that your fish get cured quickly, you need to leave your main display fallow (or fishless) for 8 weeks minimum, all of this info is in those stickies.
Also, any questions you have about this, start a thread over the fish disease and treatment section, Leebca will answer shortly.
Good luck.
