In Reply to: Online SCUBA certification? posted by Chris on November 06, 2009 at 17:11:28:

SDI has had an online nitrox course for a while- but you still have to go see one of their instructors to learn how to check your tank with an analyzer.

That course is about making sure folks know how to use their dive computer properly with nitrox rather than learning the math. SDI/TDI also have the classroom course for folks that want to learn the math.

SDA (outfit offering the course you listed) has had quite a few problems in the past- they have offered online learning for the classroom portions of an openwater course and had difficulties with former customers who found out that no one would actually honor their training and they had to start over. If I recall correctly there have been several threats of legal action.