MCU Research CO2 Scrubber

[mcallahan]

I wanted to add to the thread as it seems the useful life of the cartridges is around 2 weeks.

I've been running the scrubber for 2 weeks and I saw a nice rise in pH - from 7.85 to 8.1 for night values, from 8.05 to 8.25 for the day values.

However, the past 2 nights, my pH has dropped all the way to 7.85 again so I'm guessing the cartridge needs to be replaced. I replaced it this am so I'll watch and see how my pH recovers.

Here is my graph:

 

[Randy Holmes-Farley]

Thanks for the info.

How much did the cartridge cost you?

 

[mcallahan]

Here is what the "spent" cartridge looked like colorwise. Below is the backside of the cartridge which I wanted to show as you can see that the cartridge is not clearly spent - there are portions of the cartridge that haven't changed colors yet.

That being said, I'm wondering if some channeling is happening in the cartridge and shaking the cartridge to re-arrange the media inside would prolong the life of the cartridge.

Spent Scrubber on left, fresh scrubber on right.

Perhaps some channeling here? The top of the scrubber is clearly more purple than the bottom

 

[mcallahan]

Thanks for the info.

How much did the cartridge cost you?

$25 @ Premium Aquatics.

Once we can nail down the media used, I'm going to get a refillable DI cartridge from Bulk Reef Supply and see if I can get the same results.

BTW..I'm already using a $10 canister housing from BRS...works fine so save your $$ and buy the cartridge alone and pickup the housing from BRS.

 

[Yogre]

Please keep us updated! If we can get the price of the media down a bit I'd look at installing one of these in my system.

I can't figure out a way to get fresh air to my skimmer and opening a window in Wisconsin in January isn't really practical.

 

[Boomer]

mcallahan

That does look like channeling to me. I would shake and the tumble i.e., roll the cartridge to rearrange the media and see if you can get more color change.

You can get all that stuff here now, cheaper and higher grade media
http://www.thefilterguys.biz/

 

[Yogre]

Thanks Boomer, that's what I was looking for!

Just gotta sneak this purchase past the CINC-House and I'll be set... Been spending a bit too much on the hobby recently lol.

 

[mcallahan]

Please keep us updated! If we can get the price of the media down a bit I'd look at installing one of these in my system.

I can't figure out a way to get fresh air to my skimmer and opening a window in Wisconsin in January isn't really practical.

I'll keep everyone updated. I see running a scrubber as necessary to keep my pH up, but @ $50/month, that's too steep for me.

Here is a graph of my pH recovering after replacing the cartridge. I replaced the cartridge at the bottom of the valley in the graph.

 

[mcallahan]

mcallahan

That does look like channeling to me. I would shake and the tumble i.e., roll the cartridge to rearrange the media and see if you can get more color change.

You can get all that stuff here now, cheaper and higher grade media
http://www.thefilterguys.biz/

Thanks for the headsup!

Hmmm...looks like the filter guys got smart and starting offering bulk media.

I'll check it out. I like their stuff, but their shipping prices stink. They wanted to charge me $16 to ship me a 3 RO/DI filters.

Looks like the same thing here...$15 to ship me a gallon container. Esch.

 

[mcallahan]

Please keep us updated! If we can get the price of the media down a bit I'd look at installing one of these in my system.

I can't figure out a way to get fresh air to my skimmer and opening a window in Wisconsin in January isn't really practical.

Boomer pointed out that http://www.thefilterguys.biz/ has the media for the scrubber.

 

[Boomer]

How does his shipping stink, that is what shipping cost ? Have you checked on it ? Look at the savings you are getting vs MCU TFG 1 gal container vs MCU nonrefillable cartridges is more than a $100 saving

 

[bertoni]

I can't find a link on their home page. Sniffle.

 

[Boomer]

Jon

TFG
http://www.thefilterguys.biz/skimmer_media.htm

"skmimmer media"

 

[bertoni]

Thanks! The pages says the media turns from white to violet and back to white. What do they mean? Can it be regenerated?

 

[gasman059]

I'll be doing some testing of this unit shortly and will be adding the results here for sure.

The media is no different than soda lime used in our anesthesia machines to prevent re-breathing so in my case it should be a breeze to obtain!.

But then again at bulkreefsupply prcing it should be pretty affordable.

 

[Boomer]

No Jon you can not regen it as you are making CaCO3. "back to white" That is what happens to the color indicator once it has exhausted and turns violet. If it is left to sit, the color indicator reacts with its internal components/compounds and turns back to white,

Ca(OH)2 + CO2 ==Water/NaOH(catalyst)=> CaCO3 + H20. The "Kalk" so to speak has about ~18 % moisture.

Some do not use NaOH to include KOH, also an additive for many but are just Ca(OH)2. You end up with about 80 Calcium carbonate when these kinds of media are exhausted. There are, as you can see, different formulations of soda lime. There is a growing concern among Anesthesiologists to shift to Ca(OH)2 only, as anesthetic vapor degrades often into a number of toxic compounds, especially Compound A, a vinyl ether, when using other formulations. But for us it is a non-issue.

 

[bertoni]

Thanks, Boomer!

 

[Boomer]

You bet Jon

 

[gasman059]

No Jon you can not regen it as you are making CaCO3. "back to white" That is what happens to the color indicator once it has exhausted and turns violet. If it is left to sit, the color indicator reacts with its internal components/compounds and turns back to white,

Ca(OH)2 + CO2 ==Water/NaOH(catalyst)=> CaCO3 + H20. The "Kalk" so to speak has about ~18 % moisture.

Some do not use NaOH to include KOH, also an additive for many but are just Ca(OH)2. You end up with about 80 Calcium carbonate when these kinds of media are exhausted. There are, as you can see, different formulations of soda lime. There is a growing concern among Anesthesiologists to shift to Ca(OH)2 only, as anesthetic vapor degrades often into a number of toxic compounds, especially Compound A, a vinyl ether, when using other formulations. But for us it is a non-issue.

The main components of soda lime are

Calcium hydroxide, Ca(OH)2 (about 75%),
Water, H2O (about 20%),
Sodium hydroxide, NaOH (about 3%), and
Potassium hydroxide, KOH (about 1%).

The reaction is basically:
CO2 + H2O --> H2CO3
H2CO3 + 2 NaOH (or KOH) --> Na2CO3 (or K2CO3) + 2 H2O + Energy
Na2CO3 (or K2CO3) + Ca(OH)2 --> CaCO3 + 2 NaOH (or KOH)


There's basically two main: soda lime and baralime, the difference is barium vs calcium, mainstrem is soda lime.

The compound A theory for volatile anesthetics ie. specifically sevoflurane and the formation of compound A in low flow states has only need studied in rats and there's no clinical application. So in theory it exists but in clinical practice is of no concern although we all when using sevoflurane tend to run our machines in higher flows to cover that possibility.

The particle size and channeling provides variables for "channeling" and IMO this ceratinly can be extrapolated to what we are trying to do here.

As soon as I get this unit going in my tank I will be using our mixture of soda lime from our canisters to establish lenght and efficacy.

 

[Boomer]

Thanks Gas for the more detailed reaction and the future testing. However, not all Soda limes contain NaOH or KOH as I stated but are using, Calcium Hydroxide, Calcium Chloride and Calcium Sulphate with about ~ 15 % water.

low flow states has only need studied in rats and there's no clinical application

I do not think I could agree on rats only, at least as far as CO exposure goes, in low flow

ANESTHESIOLOGY NEWS - July 2009:

Low-Flow Anesthesia Routinely Yields High CO Levels

Dr. Richard Levy and his colleagues studied children who underwent general anesthesia at CNMA in Washington, DC. CO exposure was confirmed during low-flow anesthesia as it was regularly produced, even with fresh soda lime. This work is consistent with other studies that have also linked the presence of NaOH and/or KOH to the production of CO, but more often focused on this patient safety issue with desiccated soda lime.

The "take-home message" outlines the risk of using strong alkali absorbents during low-flow anesthesia. Their recommendation is to choose either higher fresh gas flow rates or simply use the CO2 absorbent that lacks the strong alkali metal hydroxides.