Aerator cap

[JAMbrew]

This may be a silly question but, am I supposed
To leave the cap on the aerator during fermentation?

 

[freisste]

The small cap on a 3-piece airlock? You can leave it on as there are small holes in it. If you are talking about something else, I am not understanding you. If you post a picture of the airlock, we may be able to understand and help better.

Cheers.