I have one of the Ist FFM's. I dove it quite a bit until it spooked me one day. Maybe I got spooked is a better way of putting it.
I was doing a very low stress dive and just inhaling and exhaling through my nose. My breathing was relatively slow and I was not deep breathing. During the beginning of the dive I felt fine while swimming out to the spot. After I got to the area where I was headed to and got very relaxed, my breathing slowed and I noticed things got a little "dreamy" for lack of a better term. I just felt "Off". For some reason it occurred to me that i might be rebreathing my exhalations in that mask and not getting a good gas exchange in the mask.
I dumped the air from the mask by breaking the seal and letting the air purge out by my temple. I did this for about 15 sec as I started swimming back in. Before I had even begun my accent, my head cleared and I started feeling "Right" again.
I don't know if I got this feeling because of the mask, the way I was breathing, or both. I do know it has never happened when using a mask and separate regulator though. I'm pretty sure that I was breathing some sort of Co2 buildup in the dead spaces of the mask that weren't fully circulating air. I wasn't but about 40' so I don't think I was Narced.
I'm leery of diving the mask now so it sits at home mostly. It was really nice in cold water though.
I'd might try an AGA mask or Ocean Reef with the oral/nasal cup though. I think there is better exchange of air in those masks and you don't end up with volume of stagnant air.
Be careful and have fun.
I was doing a very low stress dive and just inhaling and exhaling through my nose. My breathing was relatively slow and I was not deep breathing. During the beginning of the dive I felt fine while swimming out to the spot. After I got to the area where I was headed to and got very relaxed, my breathing slowed and I noticed things got a little "dreamy" for lack of a better term. I just felt "Off". For some reason it occurred to me that i might be rebreathing my exhalations in that mask and not getting a good gas exchange in the mask.
I dumped the air from the mask by breaking the seal and letting the air purge out by my temple. I did this for about 15 sec as I started swimming back in. Before I had even begun my accent, my head cleared and I started feeling "Right" again.
I don't know if I got this feeling because of the mask, the way I was breathing, or both. I do know it has never happened when using a mask and separate regulator though. I'm pretty sure that I was breathing some sort of Co2 buildup in the dead spaces of the mask that weren't fully circulating air. I wasn't but about 40' so I don't think I was Narced.
I'm leery of diving the mask now so it sits at home mostly. It was really nice in cold water though.
I'd might try an AGA mask or Ocean Reef with the oral/nasal cup though. I think there is better exchange of air in those masks and you don't end up with volume of stagnant air.
Be careful and have fun.
