try a low green, at 40, I can solo double up heroic 35s if they aren't casters, and I can solo no up heroic 36s, but double up 36s are too much. Also, how long did you try it, I've noticed a lot of the mobs blow through specials fast that give me an initial damage that looks like I'm not gonna be able to solo it, but it levels off and I am still able to solo them once they run out of specials.