How long will you let the scrubber sit

opheim

opheim

CCRX Supporter
Basic question - how, and for how long, are you willing to store your scrubber after a dive before replacing it in order to do another dive? A day? Week? Month? Sitting on the bench? Plastic bag? Assembled in the unit?

And will you reduce the remaining scrubbertime to account for storage time?
 
If I pack the scrubber and prep the unit, and then the dive is blown out, I will happily leave the unused scrubber in the unit however long until the next dive is. I really don't think the material goes off - there is no gas flow of CO2 while it is just standing there. So I'd be happy if that was weeks or a month or more --- although unlikely since I like to keep diving!

Overnight between dives I remove the head to let it dry out. I just leave the scrubber sitting on the table overnight. I don't bother putting it in a bag.

If I have partially used the scrubber, I always chuck it after the weekend. No point penny pinching on sorb.

Tb.
 
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My biggest worry is about the lime drying out. Not a problem once the reaction is going as breath is warm and humid, but could be at the start. So I always cap a scrubber with plastic bags (originally) before using narked at 90 bungs.

Janos
 
Forever

As long as the material does not dry out - then I let it sit forever.

There are two "facts" for this:
One beeing that a scubber actually "regenerates" some capability by sitting still after user - the main explanation being chemicals reaching equilibrium inside the sorb-pellet, which is not don ewhile its active. This gives an extended usage. Not by much, and it is sorb-dependant, but some.

Second thing, is the test done by a navy (cant rember which one, its old and on rubion) which showed no degradtion over various times - I can dig up the PDF if needed.

Third is the fact the there are no chemical reactions taking place as long as the sorb is not exposed to something that it can react with.

Keep it isolated and it will last as long as in your kegs.

Most importantly thoug - if you have any doubt, toss it out.
Also dont take anything I write for granted, check it out yourself, understand the issues, and decide. Dont trust the net :crossfing

Hanssing
 
Hanssing said:
There are two "facts" for this:
One beeing that a scubber actually "regenerates" some capability by sitting still after user - the main explanation being chemicals reaching equilibrium inside the sorb-pellet, which is not don ewhile its active. .........
Click to expand...

Care to quote a source for this "fact"?
 
The above "fact", sad to say, is a transient effect that lasts about, oh... 90 seconds once the sorb is used a second time. Paul Raymaekers did a very comlete explainaton of this in the rEvo instructors meeting a week ago at Beneath the Sea here, in conjunction with the briefing on the RMS system (which monitors the temperature of the scrubbers in 7 zones, and using this information produces remaining scrubber time). His lecture was in the context of false "extended" scrubber time calcuklation when FIRST re-using a partially used and then stored scrubber. The example was a scrubbe that had 2 hours remaining calculated at the end of the last dive. When re-used a week later it might show 4 hours remaining for the first fifteen minutes of the next dive, and then rapidly drop back to 1:45, where it belongs. There does seem to be some migration of fresh chemical to the surface of the sorb grains while in storage, but this is at the 'skin' of the grain and the effect is very transient.

Back to the question, sorb does not care where it is stored. Don't let it dry out and it will last a very long time. I have dived partially dived and then stored LAR-V scrubbers that have sat for a year (!). Paul R suggest 14 days for a partially used scrubber. For a freshly loaded and then stored one, as long as it is sealed it will last to the shelf life of the sorb.

Dave

.
 
I use EACs, so it might be a bit different. I have no problem sealing up a partially used cartridge and letting it sit for 4-6 weeks if necessary. Any longer and I get a little nervous and will relegate it for use only in the quarry.
 
As long as my faith will allow

Which is a long time when the next planned dive is short and shallow and a short time when the next planned dive is deep.

Anything that saps my confidance in the dive needs to be adressed reguardless if its a real problem or just a perceived one.

I will dive with stuff like a failed cell because its a tangable failure i can monitor and work arround. Lime is not like that and i need total faith in its function.

QED I bin a LOT of partly used lime.

When not binned its stroed in the unit between dives

ATB

Mark
 
When I return from days diving I remove head put a plastic shower cap over scrubber while cells dry off then refit head .I have left 6-8 weeks sealed like this.
 
The sorb doesn't degrade if it is sealed.

I tried this with a KISS scrubber - a long deep dive, sealed it for 6 months and then went on a other long deep dive.

No problems.

Of course, this is not a scientific test, nor double blinded, nor repeated enough to make my observations statistically valid.

I recently left a scrubber with 70 minutes on it for 1 month, and did two hour long dives today, that were ALL swimming. No issues.

So FWIW, as far as I'm concerned, there is no reason to dump a partly used scrubber if it is properly stored.

cheers

Andy
 
I saw this thread and knew your name would be popping up soon enough Mr. Del!

So why is letting the sorb dry out the problem? I would have thought the lime reacts the same way unless it gets soaked through?

I've got about an hour and a half on a scrubber from 14 days ago that I intend to use again for 2 x 45min dives this Tuesday. I had left it inside a large plastic tub with a lid, but today rebuilt the unit and now it is sitting inside that!

Just have to see how I go.
 
Tiptopperoo said:
So why is letting the sorb dry out the problem? I would have thought the lime reacts the same way unless it gets soaked through?
Click to expand...



"Dry" is a relative term. Sorb requires a specific humidity level to work, water is a part of the chemical reaction. Sorb is "wet", meaning at the level of humidity set by the manufacturer when it arrives in your jug, and stays that way in storage. "Wet" does not mean "dripping with water". It just means that it is not as dry as dust. Dry it out, meaning at the granular level and it will not work until you ADD water to it in the form of the water expired gas from your lungs. It's then a crap shoot if you get it working before you go hypercapnic.

What you do NOT want to do is to take a scrubber and let it dry out in the sun and then REALLY let it dry out. Better a little wetter than a little dryer if you are going to err on one side.

Storing half filled jugs is another way to dry out sorb until it's worthless. Keep reducing the size of the container as you deplete your jug... within reason. A month will not likely hurt a half filled jug. Ten months will, although that is dependant on the humidity of the air in the jug when you close it. Closing up a half filled jug on a humid hot day in Mississippi is a lot different than closing one up in the Mojave desert where the trapped air is so dry that it'll literally suck the moisture out of the sorb in storage.


Dave

.
 
I have put a partial used canister in a sealed plastic bag and I've been using it again after months. But, like other wise people have said, if in doubt, throw it in the bin and refill with new sorb
 
Hanssing said:
As long as the material does not dry out - then I let it sit forever.

There are two "facts" for this:
One beeing that a scubber actually "regenerates" some capability by sitting still after user - the main explanation being chemicals reaching equilibrium inside the sorb-pellet, which is not don ewhile its active. This gives an extended usage. Not by much, and it is sorb-dependant, but some.

Second thing, is the test done by a navy (cant rember which one, its old and on rubion) which showed no degradtion over various times - I can dig up the PDF if needed.

Third is the fact the there are no chemical reactions taking place as long as the sorb is not exposed to something that it can react with.

Keep it isolated and it will last as long as in your kegs.

Most importantly thoug - if you have any doubt, toss it out.
Also dont take anything I write for granted, check it out yourself, understand the issues, and decide. Dont trust the net :crossfing

Hanssing
Click to expand...

I nearly died because of posts like this.

3 days maximum storage after initial use, and then bin the sorb.
 
gianaameri said:
I nearly died because of posts like this.

3 days maximum storage after initial use, and then bin the sorb.
Click to expand...

I'd be interested in your reasoning for this, I've regulary been doing 1hour on scrubber, store it a week, another hour on scrubber, store it a week, an hour on scrubber then bin it.
For dives down to 35m.
anything below 40m is fresh lime each time.

B
 
barrygoss said:
I'd be interested in your reasoning for this, I've regulary been doing 1hour on scrubber, store it a week, another hour on scrubber, store it a week, an hour on scrubber then bin it.
For dives down to 35m.
anything below 40m is fresh lime each time.

B
Click to expand...

The most conservative of my instructors recommended 3 days storage maximum after initial use.

The least conservative used the same scrubber for one week (11 hours total) teaching a full cave course.

I generally never stored a used scrubber for more than 5 - 6 days (since after 5 - 6 days it would be fully used anyway) and used it like this quite extensively no problem, for many years, plus I read the usual stuff on the internet which you can also read in this post.

One day after only 1 day of use I had plenty margin left, but my family was coming over for a little more than 10 days... so no diving for those 10 days, be a Dad!

I listened to the voice of my least conservative instructor, and the least conservative posts on the internet, and rationalised that it was "fine" just to store and use it again after they left.

I got a bad CO2 hit, in a cave, and nearly died, because I took the least conservative course of action, out of laziness, and to save a Sofnolime refill.

It was a bad decision and a stupid one.

That is all.
 
gianaameri said:
The most conservative of my instructors recommended 3 days storage maximum after initial use.

The least conservative used the same scrubber for one week (11 hours total) teaching a full cave course.

I generally never stored a used scrubber for more than 5 - 6 days (since after 5 - 6 days it would be fully used anyway) and used it like this quite extensively no problem, for many years, plus I read the usual stuff on the internet which you can also read in this post.

One day after only 1 day of use I had plenty margin left, but my family was coming over for a little more than 10 days... so no diving for those 10 days, be a Dad!

I listened to the voice of my least conservative instructor, and the least conservative posts on the internet, and rationalised that it was "fine" just to store and use it again after they left.

I got a bad CO2 hit, in a cave, and nearly died, because I took the least conservative course of action, out of laziness, and to save a Sofnolime refill.

It was a bad decision and a stupid one.

That is all.
Click to expand...

Ok, so between dives, what was your process? what was the first dive duration? how much of the manufacturers dictated scrubber time was left? i.e. we all know 11hours on a scrubber has got to be wrong. what did you do in this instance?
(I do a 1hour ish rec dive, take can off and seal it as it is.) then assemble unit the night before the dive and place can back into loop. I never allow it to dry out in air between dives, so my total scrubber time I always limit to 3 hours.

Just wondered if there was any science behind it...

B
 
barrygoss said:
Ok, so between dives, what was your process? what was the first dive duration? how much of the manufacturers dictated scrubber time was left? i.e. we all know 11hours on a scrubber has got to be wrong. what did you do in this instance?
(I do a 1hour ish rec dive, take can off and seal it as it is.) then assemble unit the night before the dive and place can back into loop. I never allow it to dry out in air between dives, so my total scrubber time I always limit to 3 hours.

Just wondered if there was any science behind it...

B
Click to expand...

No science.

There is no science behind the topic of this thread.

My least conservative instructor set an 11 hour limit for the scrubber. It worked for him and he had done it regularly.

I have set a 6 hour limit open water and 4 hour limit overhead (but after 3.5 hours I am really not happy... so!).

Done it plenty of times no problem.

Back home I pull out the scrubber from the can. Dry the can and replace the little absorbent pad at the bottom. Put the scrubber back in. Seal the scrubber in the can overnight with a top. Let the head dry overnight before recalibrating the next day.

There are many variables we are dealing with and there is no science behind it.
 
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