Easy question for anyone who uses Aeris (I've always had Mares): Just purchased an AT 600 ION reg. The manual says to turn the pre-dive/dive switch to the (-) position. Unfortunately, I can see no markings to guide me and the photo in the manual is little more than a black blob in which you can't even tell that there IS a switch. So -- for pre-dive the knob should be turned to where the pointy end is facing up? or inward towards the mouthpiece? Thanks much.