I have a belgian tripel finishing primary fermentation after 3 and a half weeks, the yeast has finally flocculated down. I pitched one smack pack that had been in a starter for only 2 days, which was definitely not ideal pitching conditions, but it is very close to target FG. +1 on the advice of upping the temp after a week or so, I had it at 62 or so for the first week and then wrapped it with my seedling heat mat to bring temp up to 68 or 69 and it fired right up and bubbled away for 2 more weeks.