OTS Spectrum/HOG Zenith positive pressure

[viperwsu]

Yesterday I did my first two dives with my Spectrum FFM, which came as a package with a Zenith HOG regulator. The reg came already mounted to the mask and the hose, which had a band around it for the inspection information. I've never seen that before, but it looks like a regulator's version of a tank VIP sticker.

I put the reg on my AL Legend 1st stage and went diving. The experience was amazing - the first mask I've had where I didn't have a drop of water leak in, even with a full beard. Breathing through my nose the whole time was a bonus.
The only detractor was that during both dives, once I got below 15 feet or so, I could hear a rapid rush of teeny bubbles going past my ears, like a fizzing. My hood filled with air after a few minutes, until the air started leaking out of it. Nothing I did on the reg knobs or the mask straps would stop it, and if I held the mask sides where I could feel a slight tickle of the bubbles, after a second or two I felt the top of the mask start to push air out.

I'm figuring that the regulator is providing positive pressure, but I'm wondering if the shop that sold the setup (Diver's Supply) deliberately tuned it that way, or if it's an issue with the regulator, or maybe the AL 1st stage isn't playing well with the HOG 2nd? Before now I've had a AL Legend seconds.

 

[tbone1004]

@viperwsu to check if it's tuned for positive pressure, pressurize the regulator, then turn the valve off *at the surface, just as if you were checking your gear*. If it's positive pressure, then you'll be able to see the SPG needle fall as the second stage bleeds *depending on how stiff it's tuned it may take a while, so watch it for 5-10seconds. If it holds steady, then it's not tuned for positive pressure.
Assuming it is, then it's quite easy to tune it to not be, standard second stage tuning procedures as if the reg wasn't in the FFM.
Assuming it isn't tuned for positive pressure *which it probably isn't*, then any skirt leaks will cause a negative pressure inside the mask and the second stage will purge, no different than you inhaling. It's possible that you had a slight skirt leak from trapped hair from your beard, hood skirt, etc. and that was causing the slight bubble.

In a FFM, you won't notice any water coming in because it will go straight to the mouthpiece instead of the nonexistent nose pocket, so it's highly probably that it was leaking around your beard, but you didn't notice it because it went straight to the second stage.