mares octopus

Hi all,
A bit of advice reqd, I have just come back from a couple of weeks diving
in Kenya and had a problem with my Mares octopus. It seemed to freeflow on
or near the surface but was ok once I descended. Problem was I lost a fair
amount of air befor I had even started the dive.
I know there is a small nut inside the reg but do you turn clockwise or
anti clockwise to reduce the flow?
This is a fairly new reg by the way and has not been a problem befor, I
have checked the seals etc and all is fine.
Thanks for you help in advance, Neil