Malolactic Fermentation - No Airlock Bubbles?

[vouxwines]

I have a variable volume 500L tank that has been racked off the gross lees and was inoculated with MLB about a week ago. I performed paper chromatography and it would seem there is a start to the ML fermentation based on the results although no where near finishing (of course). This tank is outfitted with a bubbler airlock and gassed headspace with argon. I know ML has started based on paper chromatography results yet I see no bubbles pushing the airlock positive pressure or releasing CO2. I know ML is not nearly as vigorous as primary fermentation, but can one expect to see any airlock activity from this process or is it typical not to see that? BTW temp is 68 degrees, SO2 is under 10 ppm, pH is 3.45, and alcohol should be around 13.5 based on original Brix reading before fermentation. and finishing dry.

 

[Hazelemere]

warm it up ML goes faster warm, If you shake the carboy a bit e,g rock it you show slowly get ML bubbles

 

[vouxwines]

warm it up ML goes faster warm, If you shake the carboy a bit e,g rock it you show slowly get ML bubbles

This MLB is rated down to 54 degrees and I'm at 65, started at 70...I have barrels in the room so can't really go higher. Its a 500L tank too so can't really "shake it"...Just wondering if the airlock should be pushing positive pressure or not on a tank that size.