halocline
Contributor
When you're upside down, the exhaust valve on a conventional regulator is higher than the mouthpiece, instead of vice-versa. It's very common for small amounts of water to leak in the exhaust valve every time it opens to let out some air. In normal dive position, since the valve is at the 'bottom' of the 2nd stage, that water just drains back out. When you're upside down, the water can accumulate in the reg and drain into the mouthpiece.
This can happen with any reg; atomic, SP, apeks, whatever. It's worse if the exhaust valve is not seating especially well on the case, due to a bit of crud on the case or maybe a drying-out valve. Sometimes replacing the valve and very thoroughly cleaning that area of the case helps.
This can happen with any reg; atomic, SP, apeks, whatever. It's worse if the exhaust valve is not seating especially well on the case, due to a bit of crud on the case or maybe a drying-out valve. Sometimes replacing the valve and very thoroughly cleaning that area of the case helps.