Tricks for growing out zoa frags

[Baldy]

Hi All.

Wondering if anyone has any tips for growing out zoa frags. seems like more than half of the frags i buy end up melting. in the last couple weeks, ive bought 5 different frags of zoas. out of them, 2 are holding ok, 2 are melting slowly but steadily, and 1 melted away pretty quick. on top of that, ive got 3 other frags that i put in a long time ago that melted until they were almost gone, and are now holding. not really growing any bigger, just holding at like 3-5 heads. one of them is showing some promise, it had 2 heads for months and now just started sprouting 2 more. the one frag of dragon eyes i bought with around 30 heads half melted when i put it in, then took off. ive got 2 larger colonies from it now, but thats the only one thats taken off.

anything i can do to stop this meltdown when first introduced? theres no spiders or zoa pox that i can see, ive been keeping an eye out for those pretty closely.