After Brix dropped to 0.01 on 6.5 gallons of Gruner Veltliner, we added 15 ppm So2 and then another 20 ppm two days later... Last night (five days later) we tested and found 6 ppm free So2 and pH of 3.4. Racked into clean carboy with an additional 30 ppm So2. Twenty-four hours later we have what appears to be vigorous MLF underway... lots of tiny bubbles but not enough to move the airlock. Is this actually spontaneous MLF or is something else going on?