Sofnolime vs. Spherasorb

Randy Thornton

Administrator
Staff member
Dr Simon Mitchell (Head of Anaesthesiology, School of Medicine, Auckland University) Dr Nick Gant (Head of the Exercise Laboratory where the work took place) and Dr Neal W Pollock (Research Associate, Center for Hyperbaric Medicine and Environmental Physiology, Duke University have released a study comparing the effectiveness of Sofnolime vs. Spherasorb.

The paper, released in the Diving and Hyperbaric Medicine Journal is entitled "The duration of two carbon dioxide absorbents in a closed-circuit rebreather diving system"

Interesting read when you have a minute: http://www.dhmjournal.com/files/Harvey_TwoCO2_Absorbents.pdf

Some of you may have already heard Simon present on this at various conferences around the world.
 
Thanks Randy, it's an interesting read particularly for me as I use Spherasorb in my unit.
Thankfully I don't be doing long dives like the cave nutters :D so I just use it to lower the
WOB. I have used Sofnolime and didn't notice any difference in the WOB but it was on a
couple of shallow dives so it could be different on deeper dives.
I know State side you can get it in an HD* form that has a longer duration but this side of
pond we can't get it :(

*I think that's what it's called ;)
 
Thanks Randy, it's an interesting read particularly for me as I use Spherasorb in my unit.
Thankfully I don't be doing long dives like the cave nutters :D so I just use it to lower the
WOB. I have used Sofnolime and didn't notice any difference in the WOB but it was on a
couple of shallow dives so it could be different on deeper dives.
I know State side you can get it in an HD* form that has a longer duration but this side of
pond we can't get it :(

*I think that's what it's called ;)

Haven't hear the "HD" form term used.
 
Would be interesting to see the same comparison including Intersorb 812.
That would have been a far more interesting (and useful) comparison.

I don't know anyone that uses Spherasorb in place of Sofnolime (aside from KISS users) and can't see any sensible reason for doing so. Intersorb, on the other hand, is a similar mesh size and many people (including me) use it as an direct alternative for Sofnolime. I've been using it for more than 5 years with no issues whatsoever.
 
That report led me to question the sorb I was using. Fortuitously it came to my attention about the same time as a temp stick upgrade so I felt a lot happier about pushing things a little.

I was getting a Sofnolime product for mining refuges - colour indicating, 2.5-5.0mm grade - at a considerably lower price than 797 is available in Perth and thought I was getting a good deal. Until I compared them and discovered that 797 gives me about 30% longer on the loop. So the dollars per hour of runtime ended up making the cheap stuff actually more expensive. The cheap stuff may be easier breathing but no difference in the depths I dive and that easier breathing would have come at the expense of a shorter dwell time anyway. And the cheap stuff tended to settle and self-pack during transport a lot more than the 797, leaving me a little concerned about channeling etc.

So I've gone back to 797. At least I now grumble a little less each time I have to buy a keg: the stuff's expensive but it is still the best value around that I've seen.
 
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