I brewed a batch on Sunday and had a malfunction with a Wyeast SmackPack. It didn't swell as much as usual, but we pitched it anyway. When I looked in the pack one of the pouches with brown liquid never burst. I cut it open and poured that into the fermenter. I checked on it yesterday morning and evening, and the airlock was bubbling at a rate of about one bubble every 30+ seconds. This morning I checked it again. It was bubbling at a rate of about one bubble every 3 seconds. I've never had something ferment this slowly. Typically the morning after I brew you can see the airlock moving vigorously. At what point should I add yeast nutrients or a new packet of yeast?