live 5-10 deep: flop a flush; now what?

[mikech]

uncapped 5-10 club game, hero has about 2.5k, opponents in this hand cover. 8-handed, utg limps, lp limper, sb completes. hero raises 50 more with 9 [img]/images/graemlins/heart.gif[/img]8 [img]/images/graemlins/heart.gif[/img], all 3 others call.

flop is A [img]/images/graemlins/heart.gif[/img]2 [img]/images/graemlins/heart.gif[/img]4 [img]/images/graemlins/heart.gif[/img]

sb leads for 200, hero raises to 600, sb calls out of turn. he's told that there are players yet to act, and pulls back his 400; utg thinks for awhile and coldcalls 600, lp limper folds, sb calls.

reads: sb is a donk, will chase draws on long odds, etc. utg, however, is a generally tight player who doesn't get out of line much. he's also a 2+2er fwiw.

turn T [img]/images/graemlins/spade.gif[/img]

sb checks, hero has a little more than 1.8k left. do what?