Reefjunkie53 if you have to treat your tank for redbugs then the only way to get interceptor is to order it from Australia (Do a google search to find it). It will more than likely be the soft chews and I used them about a year ago and they worked just like the normal interceptor pills as far as dosages.
Dinky for us to help you properly you need to give us a full description of you system and recent test results also how old is your system. My original advice would be check you Calcium, Alk & Mag and make sure they are at and stay at the proper levels. From there I would check Phosphate & Nitrate to see where those levels are at. The only way to really save the corals is to get levels in check and you will probably have to cut off the dead pieces and hope the rest survives.
My urchin survived the treatment and all hermit crabs died except for one but it is a large red and it didn't effect him at all. I had no shrimp but yes it will kill them if you have them and if you want to keep your hermits alive I would remove them also. It was difficult for me to do it on a 300 gallon tank and if you do some searches on here and reef central there are steps you have to take to treat your tank properly. It is not just a mix it up and pour it in as you have to run carbon after a certain time frame, turn skimmer off, etc. You can search and find exactly how to do it!