What I do:

5 shamans
4x Ele
1x Resto

4 earth Elemental
1 Fire elemental

I have 3 dps, and one JUST kill the Pure Energy. This way the incoming damage can be focuses within one character. I can heal myself with Gift and be kept up by the resto shaman.

I do not use any trinkets, Heroism, or EM. The faster you kill this boss, the worse he is. Once he is down to 15 %, I might use Heroism if i remember, but it is not necessary.

The only macro I use this this:

/tar Pure
/cast Earth Shock

I found while learning this boss, the easier you make it, the better. Because he really is not that hard of a boss. The rest of the bosses you can brute force and still win. If you brute for this guy, you stand a higher chance of wiping. 9 times out of 10 this works. That one time will be when I am just wanting to go though this guy quickly, and keep up the Pure Energy to long and start to take a lot of dmg.