The bottom line with leathers:
I have gone through trial after trial with them, and while I could keep some of the harder corals alive, I could never keep a dang leather.
Since then I got to know a few people who really know their stuff and I found out that the above is true but it also applies to leathers themselves.
Leathers shed a skin, and the skin can kill other corals as WELL as themselves. They need good current on them to wash it off. At least thats what Im told and I have managed to keep the two leathers I dared try since then in my 100 which does have much more current in it.
Ian