Am I wrong, dude? Am I wrong?

[zepmetal]

$2/$/5 NL, players in question have about $500. I dont remember exactly, but this wasnt a huge pot anyways. Its 6 max. Table has been fairly loose/weak preflop.

I limp UTG with Ac5c. One more limper, SB completes.

Flop($20): 2d, 3c, 4c
SB bets $20, BB folds, I call, limper folds.
Is this a terrible mistake, a small one, or not a mistake at all?

Turn($60)2d, 3c, 4c) 2c
*note, i have the absolute nuts
SB checks. SB doesnt seems over aggro, but everyone is this game is known for chasing weak draws and simply choosing not to believe you at random times. Whats my action. I'd love to play ahuge pot, obviously. Is a pot building bet absolutely necessary here? How much? I figure if hes being tricky with a full house, I can get it all in on the river (these players arent good at folding hands like 2nd full). Plus, if he has a weak hand (straight, overpair, etc) he likely wont call a bet on the turn that he would call to see a showdown on the river.