Need advice about US divers Matrix Master Computer-it seems mis-calibrated

[bgda]

My daughter has been diving this week with me in Cozumel and her US Divers Matrix Computer is way too conservitive. We have been on the same dives next to each other and her computer puts her in the yellow caution zone 2 clicks while my Oceanic Data Sport keeps me in the green. (as does is my husbands Oceanic Veo 100). She even had to do a 10 ft 8 min deco stop aver a multi-level dive (90ft-then 70 and up mostly at 50-40-30 etc) 40 min dive. My computer kept me in the yellow with a 3 min safety stop while she went in to red with 10 ft 8 min deco. She was fine but I notice her computer is always 2-3 clicks further along into the yellow than mine and my husbands. Is this normal for the matrix? is there an altitude algarithym? Any help is appreciated. You can also email me at BGDA24@gmail.com

 

[KD8NPB]

I just thought I'd remark that the Matrix is a pretty old computer.

 

[jky]

Pretty normal. Are depths reading roughly the same? If so, you're probably seeing differences between 2 different algorithms.

On a trip to Puerto Rico, my 2 buddies and the dive leader were diving Oceanic computers (fairly liberal), while I was on a Suunto (fairly conservative.) They put me in deco on every repetitive dive we did.

I'd expect tweaks and updates over the years to change things (though to be honest, I'd also think that, given todays' litigious society, it would have tended to move in the opposite direction.)

jky

 

[NCadiver]

First get your manual and verify that the depth and time are correct. I think it was 60ft for 55min and 90ft for 25min. Then stop buy a dive center with a pressure chamber and verify the depth readings. It may be reading altitude incorrectly and going into its conservative mode.