Hi All
I stopped surfing in 1965, so am not up with the latest surfboard technology

I recently bought a surfboard with a Salomon S-Core inside, and have been told conflicting information about when to open the vent. Haven't had much luck researching it on the internet. Can someone please give me the real story??
Would also be interested in whether this system is still used.
Cheers,
Hemi Tuwhaaka