I have a F&P Simplus mask. Been on CPAP for three months and generally doing well except for continuing issues with insomnia. AHI in 1-3 range, compared to 30 when diagnosed. On a couple of occassions, though, my mask has -- in the middle of the night -- begun making loud noises as I inhale. It's a clacking sound. I can't quite figure out what is causing it, but have been able to fiddle with it a while and it goes away. Any ideas?