CO2 scrubber for skimmer air intake

[AaronReef]

Originally Posted by Gary Majchrzak

kalkwasser "bong"

Ha!

[Gary Majchrzak]

"bong" is the simplest way to describe the concept

ongoing research on this subject suggests that using kalkwasser as makeup water (for evaporation) is a much better (read: effective) choice in most cases.

[tmz]

Yes, limewater addition is very effective at reducing carbonic acid in the water via CO2 conversion to CO3( carbonate) but you are adding calcium and alkalinity when dosing kalk. . Using soda lime without water contact just removes the CO2 via the hydroxide in each of the blended components. Here's the Wikepedia link on it:

http://en.wikipedia.org/wiki/Soda_lime

The mixture is predominantly kalk/lime( calcium hydroxide) at 75%
Sodium hydroxide is only 3%
Potassium hydroxide only 1%
Water in the granules at 20%

I haven't heard may anecdotal accounts regarding the efficacy of this approach. Sounds promising. I wonder if passing the air through such a device would at some point impede air flow to the skimmer.

[Gary Majchrzak]

Calcium and alkalinity additions are usually a desirable thing in reef aquaria. I wondered the same thing about air flow, Tom. Nothing that I've read so far metions a decrease in airflow. I guess it depends on how well the scrubber is designed.

[tmz]

i agree calcium and alkalinity additions are usually a plus. In some cases though, an effective way to reduce carbonic acid and raise ph without adding alkalinity would be useful.

[Gary Majchrzak]

I'm thinking a CO2 scrubber might come in handy for around the holidays when we have a full houseload of guests......

[LilRobb]

Alrighty folks,

I was in a hurry typing this - let me expand on my earlier statement.

In chemistry class we all learned that the common test to prove CO2 is present is to pump air through a calcium hydroxide (water soluble) solution, calcium hydroxide 'traps' CO2 and 'makes' calcium carbonate (non soluble in water, and precipitating as white solid).
These devices can also be commercially used to remove access CO2 from ambient air - so why doesn't this work for our application if it works good for warehouses etc...

sorry if my post was confusing, I never meant the method of DOSING kalkwasser...

[tmz]

How would you do that(mechanics)without delivering precipitant CaCO3 to the air intake for the venturi? The solidified soda lime sounds more practical to me.

[tmz]

Gary, I also think it might be useful when CO2 is high in house air such as when company is in house.
I might like to use it in the summer months when the relative humidity is higher. For whatever reason when the humidity in the basement goes above 40 or 50% which is often even with a dehumidifier the ph drops. a point or so. In the winter the relative humidity hangs around 20 to 30% and ph is higher.

It might also be useful for those who wish to keep low alkalinity 7 or 8 dkh by dosing less kalk as many do with very low nutrient sps systems.

[Kent E]

I don't see how a co2 absorber is going to work in a practical sense. If you're doing a tiny scientific experiment, I'm thinking an absorber may work but on a reef tank it's a day in, day out, ongoing system. I think this would be true even with smaller 20 gallon tanks.

Would it not be more efficient and cost effective to rent an oxygen bottle and "drip" it in the intake tube of the skimmer?

And by far, the most practical concept I've heard is feeding an outside line for the skimmer, or on a larger scale an air exchanger.

I could be off on this, I'm just not seeing the bigger picture.

[LilRobb]

Originally Posted by tmz

How would you do that(mechanics)without delivering precipitant CaCO3 to the air intake for the venturi? The solidified soda lime sounds more practical to me.

Imagine a large scale bubble counter, where the air for the skimmer bubbles through the kalkwasser - no water or carbonate is being introduced to tank here...

[tmz]

Originally Posted by LilRobb

Imagine a large scale bubble counter, where the air for the skimmer bubbles through the kalkwasser - no water or carbonate is being introduced to tank here...

Ok but how would you drive the bubbles to keep pace with the suction from the air intake tube from the skimmer?

[tmz]

Kent E,
As a practical matter, I wonder about the capacity of the soda lime in a skimmer air intake application as well. It would be good to have reports from folks who have used them.

[LilRobb]

Originally Posted by tmz

Ok but how would you drive the bubbles to keep pace with the suction from the air intake tube from the skimmer?

It is self regulating - the suction of the skimmer will "pull" the bubbles through the media...