I used some slurry that was about 6 months old, really as an experiment to see how viable it still was. Fermented great, but now in the carboy there is a slight film forming on the surface, with one small whitish spot that looks like mold, but is too small to really tell. I noticed a bit of a whitish color on the krausen ring in the bucket as well. Do I have an infection or some type of funky mutated yeast? How should I proceed? I am considering just siphoning below the film and see what happens.