honestly, I would just change my class.The hydraulic class is best on heroic difficulty but if you want to use bio keep upgrading strength.
Really?
I tried legend run with bio first and got stuck on the twisted experiment
Then I tried hydraulic and got all the way to the frost zombie frost terror frost zombie battle.
So I tried bio again and realized that the twisted experiment was SIMPLE compared to that other fight.
After that I just pwned every fight because of chrystalize and Integrity
After I got legend, I trained at zone 6 to get to level 30.
Then I re-speced to speed bio(40,000 damage)
And pwned every fight again(and got the achievements old ghosts, jail break, and doomsday)
Until the twin guardians
Which I eventually beat because their electro bolt missed...
And pwned every fight again and beat the corrupter
So then I trained on hydro and beat it and realized you could get to zone 7 anyway now so I pwned every fight until the twin guardians which I eventually beat...
And beat the corrupter again...
And did a psycho and got black magic and all-star and beat the corrupter again...
Then I did another bio to get the last achievement pacifist and failed because I thought it was just 2000 damage in a single hit
So I did another bio and used reform and adrenaline and got the pacifist achievement.
Kill the weakest players first, but if there is a medic kill that one first. After that try to figure out the enemies attack and defense patterns, and don't forget to command your teamates! I might give you more but I'd have to start playing it again.