Receeding skin on a green monti cap - cause?

[ladybug5234]

I have a piece of green monti cap that was doing fine and even coloring up. I did a water change and did not realize salinity was at 1.030, maybe higher. Yesterday I noticed the edges of it are receeding. Could the salinity swing be the cause of this? If so, now that I have stabilized the salinity back down at 1.025, is there anything else I can do for the monti to stop the receeding?

Thanks in advance...