The silicone purge flapper valves can feel dry to the touch (in air), caused by salt / chemical deposits. Deposits reduce the sticktion between the flapper and the hard plastic valve seat, which can cause a minor leak.
SOLUTION:
Rinse in fresh water and
rub silicone grease into the silicone flappers. Make sure to use viscous grease from a tube, not aerosol. Dive shops sell the grease for zippers on wetsuits / drysuit,
and O-rings on camera housings. The stickiness (surface-tension) from the
silicone grease prevents the flapper from opening when minor pressure
changes might otherwise cause a burp.
TIP:
When purging out water, your head must come completely upright so that every
last drop of water flows downhill backwards towards the flapper valves.
Otherwise a few drops will remain in the purge-chamber. If water does remain, as soon as you
resume head-down position... the water flows back into the dome lens area.
SCHNOZ-POCKET UPDATE:
Our newest face-skirt works great for those with a prominant
nose bridge + other refinements. Check out the animation between
our two skirts + other details.