An airlock is just a vent, a valve to release excess co2. It's not a fermentation gauge. Sometimes they don't bubble. It doesn't mean anything. Fermentation is slowing as more and more sugar has been consumed, and consequently the yeast are farting less, so there's less EXCESS co2 needing to be venting out. Nothing more.
In a few days you can take a gravity reading if you want. But remember an airlock is not a gauge.
Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.
Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman
I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew