DIY CO2 Scrubber

[William Morris]

I found this hack searching through google the other day.
Inserted it onto my Tunze 9001 skimmer that runs in the 2nd chamber of my 32G Biocube.
I have never had a PH level above 8.00.
I test with a Apera PH60 digital meter.
I tested the meter in the 7 and 4 samples before testing my tank water.
Within 2 hours of putting the Scrubber into play my PH reading was 8.12. Yeow.

I used Jorvet Soda Lime (amazon) because the reviews on the BRS Soda Lime are not very good right now.
Also used a Salter Labs water trap - link to Amazon: Trap

 

[Reefs and Geeks]

Nice, I tried something very similar with a glass column I had laying around in the past with success as well. I've since upgraded to a DIY scrubber made from a spare water filter housing. I notice more of a change with more media than I had in the glass column, and change out the media much less frequently. The glass column was much easier to hide by the tank though. I'm also using the same soda lime with good results.

 

[Fernthereefer]

I like the idea, but how long does it last? usually we use big chambers for the soda lime to last a few weeks.

 

[Randy Holmes-Farley Verified Community Expert]

My DIY involves any cheap sodium hydroxide dissolved in water. The air is bubbled through it to remove CO2 from the air. I never needed to use a scrubber on my reef, but I have used that in a lab to remove toxic gases. I know a few folks use them on reefs.

 

[Reefs and Geeks]

My DIY involves any cheap sodium hydroxide dissolved in water. The air is bubbled through it to remove CO2 from the air. I never needed to use a scrubber on my reef, but I have used that in a lab to remove toxic gases. I know a few folks use them on reefs.

That's a really interesting idea. Any chance you could post a picture of your setup? How long does your sodium hydroxide mixture typically last for you before needing replaced?

 

[Randy Holmes-Farley Verified Community Expert]

That's a really interesting idea. Any chance you could post a picture of your setup? How long does your sodium hydroxide mixture typically last for you before needing replaced?

As I said, I've not used it on a reef, but it is widely used by scientists.

The soda lime that has so taken the reef community is mostly used in special environments where bulk liquids are not desirable, such as for a diver. That material is much more expensive.

 

[homer1475]

So basically water and lye in a reactor with the skimmer air plumbed into it sucking air out of the canister where the entering air is bubbled through the mixture?

That might actually be easier and cheaper then soda lime.

 

[homer1475]

Any recommendations on concentrations?

 

[Randy Holmes-Farley Verified Community Expert]

So basically water and lye in a reactor with the skimmer air plumbed into it sucking air out of the canister where the entering air is bubbled through the mixture?

That might actually be easier and cheaper then soda lime.

It is certainly far cheaper. It may be a little harder to implement as you need to get the air to bubble through the water.

 

[Randy Holmes-Farley Verified Community Expert]

Any recommendations on concentrations?

Doesn't matter too much. 10% NaOH is a good place to start. Sodium carbonate will precipitate from it as more and more CO2 gets trapped.

 

[homer1475]

Why harder?

In my simple mind, a reactor plumbed backwards so air is pulled in from the bottom and out the top, should bubble. No?

 

[homer1475]

I've never been a huge fan of soda lime, but did use it for a while. While I noticed a great increase in my PH, the cost was prohibitive to using it for me.

This is most certainly cheaper, just don't see any issue with getting the air to bubble through the sodium hydoxide if your using a reactor(very similar setup to a soda lime setup).

 

[BranchingHammer]

The resistance of the weight of the water will make it to hard for the air to bubble through the reactor and the skimmer pump will probably only pump water rather than a mix of water and air.

 

[homer1475]

The resistance of the weight of the water will make it to hard for the air to bubble through the reactor and the skimmer pump will probably only pump water rather than a mix of water and air.

Didn't think of that. Thank you. I have a spare reactor laying around, and the day off. Might give this a try today.

With what was said above in mind. I wonder if an air pump pushing air into the reactor would overcome the weight of the water issue? I'm thinking a large reactor canister where there will be a large volume of air above the water/lye solution.

 

[BranchingHammer]

That's what I was thinking, using an air pump to bubble air into the bottom of the solution, and then harvesting air from the top of the container. You would probably need a vent hole too if the container was air-tight in case one side pushed/pulled more than the other. I might try this, but I don't have any sodium hydroxide. I might try it with kalkwasser instead because the solution will just precipitate out calcium carbonate instead. That being said, sodium hydroxide has a much higher solubility, so it will be much more efficient and less messy too.

 

[Randy Holmes-Farley Verified Community Expert]

Why harder?

In my simple mind, a reactor plumbed backwards so air is pulled in from the bottom and out the top, should bubble. No?

Yes, but there is some back pressure on the air to go under water, so you may need to pump it so you do not inhibit inflow to the skimmer..

 

[homer1475]

Local hardware store should have lye. I actually have it to dump in my toilet from time to time.

Would food grade lye be any different then lye used for drain opening? Obviously the purity could be an issue, but using it in this manner, purity shouldn't be a concern?

 

[Randy Holmes-Farley Verified Community Expert]

That's what I was thinking, using an air pump to bubble air into the bottom of the solution, and then harvesting air from the top of the container. You would probably need a vent hole too if the container was air-tight in case one side pushed/pulled more than the other. I might try this, but I don't have any sodium hydroxide. I might try it with kalkwasser instead because the solution will just precipitate out calcium carbonate instead. That being said, sodium hydroxide has a much higher solubility, so it will be much more efficient and less messy too.

Kalkwasser will work, but may be less effective because the pH is much lower than sodium hydroxide. hence the tendency to hold CO2 is lower.

 

[BitReef]

I found this hack searching through google the other day.
Inserted it onto my Tunze 9001 skimmer that runs in the 2nd chamber of my 32G Biocube.
I have never had a PH level above 8.00.
I test with a Apera PH60 digital meter.
I tested the meter in the 7 and 4 samples before testing my tank water.
Within 2 hours of putting the Scrubber into play my PH reading was 8.12. Yeow.

I used Jorvet Soda Lime (amazon) because the reviews on the BRS Soda Lime are not very good right now.
Also used a Salter Labs water trap - link to Amazon: Trap

Any report yet on how long the soda lime lasts in this setup? How often do you have to change it?

 

[Randy Holmes-Farley Verified Community Expert]

Local hardware store should have lye. I actually have it to dump in my toilet from time to time.

Would food grade lye be any different then lye used for drain opening? Obviously the purity could be an issue, but using it in this manner, purity shouldn't be a concern?

Drain opening lye is fine, as long as it is the only ingredient.