Hi all, I'm making a brew w/OG of 1.065, re-pitched a slurry of Pacman Yeast,prob about 5 cups to 12gal batch, pure oxy for 90sec. It took off in about 4hrs, went like crazy. Just checked after 8 days and I'ts only 1.020. Should I do nothing yet, or toss in some yeast nutrient, and if so, about...