Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
DeepScuba:Incase no-one here will help you............
Go over to TDS and do a search. I have seen it on there. Either that, or ask Doppler about it (Ask on TDS, he's not here often).
From my understanding it is with specific mixes.