Partially Used Scrubber

How long before dumping a partially used scrubber?

  • Dump after every use. Can't be too careful.

    Votes: 7 5.3%

  • If I'm using it tomorrow I'll bag it up.

    Votes: 13 9.8%

  • I'm going diving next weekend. Sorb will be just fine sealed in the unit.

    Votes: 24 18.2%

  • 2-3 weeks. Eh, there's only an hour on this one so four weeks should be OK.

    Votes: 46 34.8%

  • It's been sealed in the canister with an airtight lid for a few months now. Let's go diving!

    Votes: 42 31.8%
  • Total voters
    132
nickb said:
The tape is right there on the scrubber and I always remove the scrubber at the end of the day to dry the head. Can't help but see it.

I don't keep a log book, but if I did it would require an extra step.
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I do the exact same thing. Never had an issue.
 
personally I don't bother with a logbook or tape. if it's so long ago I can't remember how long the scrubber has on it I bin it. lime is cheap compared to my life.

though TBH it's fairly easy to check using the following method that generally requires me to be able to count upto, and remember, the number 1 or 2 as most dives are a minimum of an hour long.

- hmm let me think, have I done one dive or two dives already on this scrubber?
- two? yep two cos I changed it out ready for that dive last saturday and I dived on wednesday as well.
- good two, now how many minutes have I done on it?
- hmmm let me think? how about I look at the divelog on the controller attached to the unit and add the last two numbers together? could that possibly be almost exactly how long the scrubber has on it less a couple of 2-3 minute pre-breathes?
 
Different strokes. Mines out of habit from my old inspo days. I use to have 3 scrubs so I'd date them when I filled them anyway. Whatever anyone wants to do to ensure they arent about to breath used up sorb is cool with me.
I had a temp probe take a dump and was diving non rms. A series of short dives while I was balancing some projects im working on. So I did like 5 dives on 1 scrub. But you are correct. In 99% of my diving after dive 2 dump. Pretty easy.
 
My log book is electronic and from it you can also check if the scrubber is one/two/... dives old from the log books itself.

Here's 15 mins into 2 dives 3 weeks apart on the same scrubber.

Matt.

stick-15mins_zps6biyjsrc.png
 
lizardland said:
I only raised it as I've twice had chesty symptoms soon after using part used scrubbers after a winter lay up. I used to be sceptical of stuff living in there. My day job used to be designing waste processing plants and I've seen "stuff" (not a biologist) growing in caustic enough environments that the atmosphere was eating through steel cladding. I'd love to know if it was just my paranoia or if there was any truth to it. I know, start the season with fresh lime... I'm Scottish, throwing perfectly good, five month old, partially used lime away doesnt come naturally :)
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Don't have any proof but I would guess the bacteria grew in the loop somewhere and not in the lime. I frequently store partially used scrubber in my HH can. I pull the scrubber out and wipe out the can then replace the scrubber and seal it with a lid. This allows the sorb to be sealed and the rest of the loop to dry out.
Regardless it will be nice to find out if this common practice is a good idea or not.


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Michael Thornton said:
Don't have any proof but I would guess the bacteria grew in the loop somewhere and not in the lime. I frequently store partially used scrubber in my HH can. I pull the scrubber out and wipe out the can then replace the scrubber and seal it with a lid. This allows the sorb to be sealed and the rest of the loop to dry out.
Regardless it will be nice to find out if this common practice is a good idea or not.


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Everything but the scrubber cartridge had been virkon'd and dried. Loop hoses, BOV components, counterlung, lid, absorbent pads, even the centre section had been removed from the frame and soaked (Mk15 so it'll tolerate getting this wet). The only thing that hadn't been disinfected was the scrubber because I figured nothing would grow in it.

Whole thing was done at the start of the lay up and then the day before going back in service.

Whether it was the lime itself or a component of the scrubber cartridge, who knows?
 
Michael Thornton said:
I frequently store partially used scrubber in my HH can. I pull the scrubber out and wipe out the can then replace the scrubber and seal it with a lid. This allows the sorb to be sealed and the rest of the loop to dry out.
Regardless it will be nice to find out if this common practice is a good idea or not.
Click to expand...

I never seal the partially use scrubber. If diving soon I leave the cartridge on my workbench. If it will be a while (more than a week) then I assemble the cartridge into the canister and leave the hoses disconnected. Never had a problem. YMMV
 
Isn't air flow required for the reaction to happen and also to dry it? I can't see it going 'bad' by just sitting around.
 
As i understand not even airflow. It would only dry out the lime with time. As long there is no co2 how could it react?.
I am happy to let it sit for months. Did it before without any issue. Imho
But if you do not feel comfortable with it, bin it. It is your life and choice
 
Fascinating thread and really interesting to read so many views on this topic, this survey and the trials described is long overdue.

Personally I leave my radial scrubber on the bench for ~24hrs in an airy place to get the moisture out then seal it in my meg canister. I dive every 2-3 weeks so storage can be +2months.
 
Sorry to drag up such an old thread, did anything ever get published from Simon's research that gets mentioned in the thread?
 
Paulo said:
Sorry to drag up such an old thread, did anything ever get published from Simon's research that gets mentioned in the thread?
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There are a number of relevant useful publications by Simon as follows:
  • The five-minute prebreathe in evaluating carbon dioxide absorption in a closed-circuit rebreather: A randomised single-blind study - here
  • The duration of two carbon dioxide absorbents in a closed-circuit rebreather diving system - here or here
The one element of the team's research that has not been published to my knowledge is "How effective are scrubber monitors at predicting CO2 breakthrough". Remember their study was with Revo and Inspiration and may not be applicable to other CCR. The outcome was

Temperature-based monitors:
  • Reliably predict breakthrough at resting workrates
  • Do not predict breakthrough at exercise workrates
  • Do not predict breakthrough with Spherasorb
CO2 gas monitoring:
  • Provides valid warnings in a lab testing environment
  • Increases monitoring reliability when combined with temperature monitoring
 
Paulo said:
Thanks. Anything about reusing stored, part used scrubber??
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Keeping it in a sealed bag is apparently better than otherwise, but I never bother and have kept a part-used scrubber on a shelf for months without any problems.
 
Cheers Nick, I put mine in a small plastic bag and leave it loosely wrapped. I do notice that scrubber that gets left for a week or so goes hard when I empty it, primarily at the bottom of the stack, sometimes at the top of the stack too.

Wonder if that has any effect on performance or WOB?
 
I remember reading of an accident a few years back. The failure was traced back to partially used scrubber media that was removed from the scrubber housing, stored and put back in and used some more. While there was therotically enough life left in the scrubber for the planned dive, the dumping and refilling of the scrubber messed up the reaction front in the scrubber. The way the scrubber was repacked left channeling that resulted in the failure. If the scrubber would have been left packed it would have been fine.
 
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