we did it in 16 man,
When we have tried it in the past in 8 man it was just too much for only two tanks to deal with .
Like I said, it's doable with 2, but only if the DPS and healers are on point, too. The tank with the debuff needs to be able to kite adds (we usually have the debuffed tank kiting one add at a time while the other tank kites the rest) and have the DPS burn the single add down before he takes another. In my experience, if the DPS are trying to AOE, they're going to pull off and people will die.
If they're single-target attacking the one add, someone will pull off, but it'll die before it reaches anyone, generally. Then the tank picks another one and does it again. By the time 2 of the adds are dead, the debuff should be gone anyways and it's safe to just tank the remaining two.