I do this with an earth elemental and 4 ele shammies. I stand away from the earth ele, just heal a few times for him to get some aggro, then i start a very very simple rotation...

lb, lb, lhw, lb, lb, lhw, lb, lhw...repeat. When he raises his hammer, i switch to lb, lhw...repeat. I don't pop heroism or trinkets and only had like 3 s2 epics on me while doing this. Your shammies shouldn't be taking the dmg, and the tank is easily spam healed through the dmg. Your prot pally has much better stats than a 7k hp earth elemental.