ive had to start feeding the tank more due to the crabs hunger for meat. they are eating my snails.
If your hermits are eating your snails, then there is a pretty good chance that they're bothering your worms too, although that wouldn't explain why your smaller worms are fine. I mention this because I had problems with my blue-leg hermits constantly harassing my feather duster worms. Finally, I decided to go crabless and my tank has been much more peaceful ever since. I now have snails only in my clean-up crew.
Brenden's right, 1.027 is not that high, however you may not have been acclimating them slowly enough to it.
Those are the only two things that I can think of. HTH