A3 flops two pair from BB

[bmxreed36]

This might just be a simple hand but I never feel real comfortable flopping two pair OOP in multiway pots. Generally I play them pretty aggressive from the start and routinely bet out around the pot. I normally bet 600 in this spot but this time I guess I made it 450. Anyone go for a check-raise on the flop? Different bet amount? And what should be the plan for the turn here? Again, it might be a standard hand but I was just wondering how others might play it. No reads btw.

PokerStars No-Limit Hold'em Tourney, Big Blind is t150 (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

CO (t28105)
Button (t11864)
SB (t5350)
Hero (t14945)
UTG (t8586)
UTG+1 (t7600)
MP1 (t30085)
MP2 (t22610)
MP3 (t23035)

Preflop: Hero is BB with A[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/heart.gif[/img].
UTG calls t150, <font color="#666666">4 folds</font>, CO calls t150, Button calls t150, <font color="#666666">1 fold</font>, Hero checks.

Flop: (t675) 2[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets t450</font>, UTG folds, CO calls t450, Button folds.

Turn: (t1575) 5[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)

[Chrisman886]

I like the flop. Betting out here disguises your hand nicely. The bet size is fine too. I think its extremely unlikely he has a 4 here on the turn so I continue to pound away. I'd bet 1k here probably.

[Habib Marwan]

The bet on the flop is alright, although i like betting 500-600 on the flop. Turn make it 1100 or so and value bet a good river. If you get raised, MAYBE consider folding.

[bmxreed36]

OK, might as well include the rest of the hand. I bet 750 on the turn which even at the time I knew was too small. I don't remember what crossed my mind to make me do that at the time but I remember I hated the size right afterwards. Anyways, CO calls again and river is 8 of diamonds. I bet 1000 now (good example of blocking bet?), CO raises to 3500 and I fold. I regret not betting the turn bigger but any other comments? River OK?