frost pvp> kara Follow

Hey i read alot of post about fire and frost and arc....but i have a ? with a frost build say in kara or pve stuff does water ele even mater even in pvp arena...I was frost> then switched to fire im 69 at the moment... and i want to do kara but stay as frost.. they say 700 spell dmg u need to do that kinda stuff.. ok thats fine with me i took up enchantment to gt up thier in spell +++ but when u go agenst a fire mage in dmg do they add the water ele or just each other dmg.. i havent seen a post about that.. well just wondering about the water ele in pvp and pve.. if its worth having or what if so.. can somone give.. me a build with frost ele..... and one with out....fire is cool but mana shield pisses me off if i get hit hard enuff i loose alot of mana and i hate that thats why i like ice shield thing It only cost mana at start.. but dont drain u when fighting......so any ways let me no about that water le for pvp or pve.... thanx if its not worth it ill just stay fire....;;

ya my bad on the writing im special... i ware a helmet....and a name tag sorry...But ya i know about the dmg but im asking if the water ele is counted in the dmg and how good is it in kara and pve