2 tanks needed too. The first tank will get Tsulong and face it away from the raid, the other tank should stay close, on a side. Tanks MUST switch on each Shadow Breath, as it increases shadow damage taken a lot. The "new" tank MUST taunt facing Tsulong away from the raid.
On phase 2, a tank should get the big Add and the other the small adds that spawn. If you can't complete the boss on a first attempt, just repeat.
When you're taunted off shadow breath, you should go to the light beam and clear your debuff stacks to minimize the damage taken and make your healer's life easier.