100NL, Float & bluffing line on turn, how about river?

villain is unknown. I was tempeted to try float and bluffing line in later streets. Do i have to give up ? If i follow up, how much do you guys think i should bet to get him off and save some money just in case he has real hand?

PokerStars Pot-Limit Hold'em, $1.00 BB (8 handed) Poker-Stars Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG+1 ($100)
MP1 ($78.50)
MP2 ($99.90)
CO ($115)
Hero ($93.50)
SB ($95.85)
BB ($99.75)
UTG ($34.40)

Preflop: Hero is Button with 5http://www.flopturnriver.com/phpBB2/...iles/heart.gif, 5http://www.flopturnriver.com/phpBB2/...miles/club.gif.
4 folds, CO raises to $3.5, Hero calls $3.50, 2 folds.

Flop: ($8.50) 6http://www.flopturnriver.com/phpBB2/...iles/heart.gif, Jhttp://www.flopturnriver.com/phpBB2/...iles/spade.gif, 8http://www.flopturnriver.com/phpBB2/...es/diamond.gif (2 players)
CO bets $4, Hero calls $4.

Turn: ($16.50) Khttp://www.flopturnriver.com/phpBB2/...iles/spade.gif (2 players)
CO checks, Hero bets $10, CO calls $10.

River: ($36.50) 8http://www.flopturnriver.com/phpBB2/...iles/heart.gif (2 players)
CO checks, Hero ??

Vs unknowns this is like dancing on the edge.

Given the pretty dry flop ur repping 79/T9/66/88 and maybe Jx, tho we´d probably raise a JT on flop. To pull a profitable move on river, we must know what´s his range, so we can figure out how his range will react to certain bets, and its not that easy to put ppl on a range when ur blindfolded. Definetly in his range are 99-TT and T9, depending on his postflop tendencies Axss and Jx and other stuff.

I´d go for $22 on river

hee hee, its exactly the amount of money i bet to get this job done. :P
if i have good feeling and smell obvious weakness , i am ready to attack anyone except very tricky guys. 100nl ppl are just really weak passive and easy to be pushed around when they cb weak and go check/ check mode later.