I racked off my gross lees last night and added MLF yeast to my cabernet. Room temp is 70. As of this morning, still no bubbles. Should i be concerned? If not, how soon should i see some sort of activity?
MLF is a slower process than AF and it'll take longer to get going. Also, the bubbles are smaller, the residual sugar is less, and the MLB don't generate nearly as much CO2 as yeast. Keep the temp up, the O2 exposure down, the pH level above about 3.3 and you should see results soon. Also, some MLB nutrient (not yeast nutrient) will help the process along.
P.S. I just noticed you said you added MLF yeast. I assume you meant MLF bacteria because it's bacteria, not yeast, that do MLF.
I now have clusters of tiny bubbles on top so it looks like its starting. No real noticeable movement but its something. I have a test kit so i can test it when i stir the lees in a day or so. I also "borrowed" some argon from work which i will disperse with my high tech balloon gas dispersion device so i can limit the oxygen contamination.