backup computers: several questions-need opinions

[scubadada]

My primary is an AI Oceanic VT3, backup is a Geo2 and a SPG. The computers are perfectly matched running DSAT without conservatism. I would have matched computers running the same algorithm. If that's not possible, a flexible computer like an Oceanic running dual algorithm and various conservative factors may be likely to closely match the algorithm of a different brand. As pointed out, the main purpose would be to continue a series of dives without any interuption or compromise in safety.

 

[clownfishsydney]

You only need one backup between you and your wife. So long as you dive together (and one does not hang continually above or below the other), then the profile will be roughly the same, certainly close enough for later use. If one of you does not do a dive on a holiday, the one who does takes it. Then, if your main computer dies, you take the back up. It must do every dive on the trip that one or both of you does.

If you do not do multi day trips, then why bother. Your wife's will be close enough to use if your's fails.