Regulator problem

[Jwood]

any thoughts folks?
Was diving on Sunday, depth was approx 100' temp at bottom like maybe 41*
I have had some problems in the past with free flows at lower temps
I dive MK25/600..........
The problem: at about 90' my reg starts to get real hard to draw on, then no air
I switch to my back up, I take a breath then try my primary again....its a hard draw but I can get air, I purge thinking this may rectify problem........still hard draw. I switch to back up again and call the dive.....while heading back I try the primary....and everthing is working fine??????????????????????
Any thoughts would be appreciated
Thanks

 

[redacted]

Assuming your octo breathed OK and the purge of your primary was reasonably strong, I'd start by looking for something that might be interfering with the lever operation in the 2nd stage.

If the purge was also weak, I'd look at the hose.

 

[Diver0001]

any thoughts folks?
Was diving on Sunday, depth was approx 100' temp at bottom like maybe 41*
I have had some problems in the past with free flows at lower temps
I dive MK25/600..........
The problem: at about 90' my reg starts to get real hard to draw on, then no air
I switch to my back up, I take a breath then try my primary again....its a hard draw but I can get air, I purge thinking this may rectify problem........still hard draw. I switch to back up again and call the dive.....while heading back I try the primary....and everthing is working fine??????????????????????
Any thoughts would be appreciated
Thanks

Were your primary and secondary connected to the same first stage?

R..