I'm making a Black IPA. Primary fermentation slowed and I racked into secondary where I dry hopped. Fermentation really picked up so much that I had to attach a blow off tube. It slowed down after about two days and has been fermenting for about 3 weeks at a constant rate. Enough to be able to see bubbles rising. Room temperature is maintained between 66 to 70 Degrees. Why is the secondary taking so long and is this normal and ok?