I played this hand a little earlier today, would like your thoughts, was it the correct play? I won the hand but that doesn't always make it a good play.

Golden Riviera $20 NLHE 10 max ring game

Hero is UTG+1

UTG fold
Hero raise $0.80
UTG+2 fold
MP1 fold
MP2 call $0.80
CO call $0.80
Button fold
SB call $0.70
BB call $0.60

Flop $3.75

Hero bets $4
MP2 fold
CO call $4
SB fold
BB fold

Turn $11.70

Hero checks
CO bets $5.20
Hero raise all-in $13.70
CO fold

Hero wins $30.60

A total bluff, betting on the river, I know but it worked. The CO seemed a solid player and had me covered when I was all in. I put him on 2 pair (J9) or a set (5s) would this seem a fair assessment?

I think it's a risky spot to bluff as the pot is ~$20 and your raise is only $8 more, but if you gave him a good chance of folding then it's not a bad move as you still have outs even if he calls.

Looking at the math (someone please correct me if I've made a mistake, I'm a little rusty at this): you're getting a little better than 1:1 on your bet so if his fold % plus your win % the times he calls together is around 50% or greater then it would seem to be a good move. Since you'll hit the flush about 20% of the time he calls he would have to fold between 60-65% of the time for your win % to be at the 50% mark.

That's a pretty high fold percentage, especially considering he's already put in $5 on this street and the pot is laying him 2.5:1 on his call, which again shows that it may not be the ideal time for a bluff.