Marine stock doest fare well with swings in temp, especially inverts such as corals. Marine ich is also treated differently than FW ich.
I only feel safe with 2 different types of treament and those include hyposalinity and copper. These are ONLY safe for fish. They will kill inverts (snails, crabs, featherdusters, corals, etc.) and much of what lives in the live rock. For this reason these types of treatments are performed in a hospital tank under close supervision. The copper treatment must be done in conjunction with the appropriate type of copper test kit and the hyposalinity method must be done with a refractometer not a hydrometer. All fish should be treated even if they don't show signs of it yet and the display tank must be left fallow for a minimum of 6-8 weeks. Otherwise the parasite will not have had time to go through the cycle without a host. Without a host they'll die. No fish, no host....and then I believe you can rid your tank of ich.
There are other opinions on ways to treat marine ich but the ones above are what I personally feel comfortable with.
I only feel safe with 2 different types of treament and those include hyposalinity and copper. These are ONLY safe for fish. They will kill inverts (snails, crabs, featherdusters, corals, etc.) and much of what lives in the live rock. For this reason these types of treatments are performed in a hospital tank under close supervision. The copper treatment must be done in conjunction with the appropriate type of copper test kit and the hyposalinity method must be done with a refractometer not a hydrometer. All fish should be treated even if they don't show signs of it yet and the display tank must be left fallow for a minimum of 6-8 weeks. Otherwise the parasite will not have had time to go through the cycle without a host. Without a host they'll die. No fish, no host....and then I believe you can rid your tank of ich.
There are other opinions on ways to treat marine ich but the ones above are what I personally feel comfortable with.