Don´t triple, bluff with hands like 97s, 86s etc. instead. Your A-high even has some showdown value against his floats / draws, so you win less by bluffing with A-high instead of 8-high - and you can´t barrel all, even less on NL10 where the average player rather folds too little than too often.

Don't bluff this runout at 10nl. He's pretty likely to have Jx which he's never folding and like BigFiszh said you actually have a small amount of showdown value.

I'd stay away from bluffing when the turn en river brick. He's never folding Jx and I doubt you can profitably  get him off a 9, since they never fold at those stakes.
I'd also think about folding A7s pre-flop and betting every street a little bigger as a standard, though I think this board is a decent one to bet a little smaller on.