Your gear is perfectly alright for Jan'alai.
Try to find the source for why you get owned at ~25%.
Have a look at your combatlog - this is helpful and will let you know why you died - giving you the opportunity to adapt your style of tanking.
So for instance check if he crushes you a lot try to concentrate on your SB. Should you get a lot of Damage from the exploding eggs concentrate on your positioning etc.
Another source of faliure could be healing: Have you spoken to your healers? Maybe they run out of mana. Or probably you have a retardin / drood devoted for MT healing who tries to help out with group healing.
Hoping that helps you...