Tablet [Q] parental control issue nexus 7(2013)

on my d link router.....2 windows 7 computers,2 iphones,2 nexus 7(2013) tablets are connected.....i want to block all adult content from one of the tablets.....i know nexus 7 offers setting up of alternate user,but i dont want to use that......ihave a dlink 2750-u modem router......so how can i use either opendns or dlink parental controls to block adult content to one of the tablets only....i even have access to the google account to which the nexus 7 is linked to........i would prefer step by step instructions
thanks in advance