A question about semi-bluffing

PokerStars 0.25/0.50 Hold'em (7 handed) FTR converter on zerodivide.cx

Preflop: Hero is BB with J[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/spade.gif[/img].
<font color="#666666">1 fold</font>, MP1 calls, MP2 calls, <font color="#666666">1 fold</font>, [TSPECIALAMPERSANDA]Maximus calls, SB completes, Hero checks.

Flop: (5 SB) Q[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, Hero checks, MP1 checks, MP2 checks, [TSPECIALAMPERSANDA]Maximus checks.

Turn: (2.50 BB) K[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, MP1 folds, MP2 folds, [TSPECIALAMPERSANDA]Maximus folds, SB calls.

River: (4.50 BB) 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, Hero checks.

Final Pot: 4.50 BB

On the turn, am I being too aggressive here by semi-bluffing into such a large field? Also, despite the strength of my draw, is the risk of a reraise too high? This sort of situation comes up often for me. Nobody shows much interest on the flop, I pick up a strong draw on the turn, and my natural inclination is to bet, but I'm totally unsure about how profitable of a play this usually is.