[Foucault]

You have to bet more on the turn. Although you're denying him the odds for either a flush draw or a straight draw and he probably doesn't have a combo (at least he shouldn't, with his passive line), you don't know which one he has. Even not particularly good players can bluff scare cards when you check to them on the river, which means you've got to charge him for his bluff outs as well on the turn. And you might as well bet the river, because he calls with one pair hands a lot more often than he bluffs busted draws.