Those 'fuzzies' are probably just root hairs if you don't cover the seeds while growing. You'd know if you had mold. I cover my seeds with a thin layer of Potting Mix. A couple of things you might try are.....(1) Grow in a well ventilated area (I grow my WG under a ceiling fan) and (2) Use a little Hydrogen Peroxide in a Spray Bottle and lightly 'mist' and (3) Don't overwater.......WY