As far as I'm aware, when I run a timer for my guild the enrage timer is 5:45.
What you can try doing (if you only use dps for the red pools) is having a Merc or Operative healer standing in the first red pool, this gives the dps a bit more time to attack the boss. Using this method we have the Writhing Horror dead before the 4th red pool.
Although, if you're struggling on the enrage timer for this fight, which is fairly generous, and are all 61 / 63 geared, your dps just aren't putting out enough damage. Ask them to enable combat logs on the fight and to upload them to www.torparse.com
, if they're below 1400 you will have problems.
If your dps are 61/63 geared and below 1400 on that fight, then it's their rotation.