Water/lightning shield question

Trying to get my macro to autocast shield water for solo play lightning for groups but cant seem to get it setup right, looking for a little help. been using this string in multiple ways but no success. Its been a while since i played and maybe im missing something, is this only able to be used as tracking the mobs debuffs?

/castsequence Water Shield(Rank 2), null

/castsequence reset=combat/ctrl/alt/shift Water Shield(Rank 2), nomore

Better to use the smartbuff addon to be fair which buffs at your leisure with the mouse wheel.