<a href=showthread.php?s=&postid=7418372#post7418372 target=_blank>Originally posted</a> by Fliger
I would bet money that its a stability issue. Alkalinity and salinity have to be ROCK SOLID, and its extremely hard in such a small tank. Throw on a protien skimmer and it can even exagerrate the problem by bouncing your salinity around.
Small tanks are very difficult unless you know exactly what you are doing. Tip recession and STN IME are signs of basic stress from unstable conditions.
Make sure you have a good refract. and measure your salinity between topoffs. Also measure your alkalinity daily. And make sure your WC water matches your tank water in terms of salinity and alkalinity.
I could be wrong, but every time I've ever seen those signs - its because I wasn't on top of things. A few times I took those frags to friends houses and they healed up practically over night.