JeF4y's DIY CO2 Scrubber!
I showed this off at the reef club meeting this last week, and promised I'd do a bit of a write up on it, so here goes.
My idea was a CO2 scrubber.
What is a CO2 scrubber?
Good question! A CO2 scrubber is simply a small external DRY reactor which holds media that extracts excess CO2 from the ambient air.
Why use a CO2 scrubber?
The primary benefit of a CO2 scrubber is a higher pH in the tank.
How does it work?
The CO2 scrubber is simply a reactor holding media called SODA LIME (which is mainly comprised of calcium hydroxide, yep, that same pickling lime you use/see in kalkwasser - yet in a different media format). Soda Lime is commonly used in medical equipment and re-breathers for divers or firemen, and is a granular media which absorbs CO2 from air as it is drawn (or forced) through the media.
Details
There are many causes for low pH in tanks, and the cause we are combatting here is high CO2 levels in the ambient air which gets introduced into the tank through our skimmer air intakes or even through water trickling which breaks the surface tension.
In the Jack Kent presentation at the ARC meeting on 7/28/12, he stated that homes can have a CO2 concentration of 1000-5000ppm in the air versus something like 200ppm in fresh outside air. That CO2 gets introduced to the tank through your skimmer air intake or as mentioned above, any trickling water, etc. And this can (and does) affect your pH, lowering it.
The CO2 in your house comes from may places, mainly people & pets. The issue is that without extreme ventilation it has no place to go and will build up to levels much higher than that of outside air.
One way of combatting this is leaving a window open, or running skimmer intake lines to the outside of your house. The issue with those solutions is that it's not always safe or comfortable to leave windows open, and running a skimmer line outside gives you the risk of dirt, dust, pollen, insects, pollutants or possibly pesticides being introduced to your tank. The CO2 scrubber sits in your house and provides the same function for minimal cost.
You can buy commercially available reactors & media from reef stores for around $100 for the initial setup and then $50 for a small amount of media, but this DIY will run under $100 and give you enough media for a year or more.
ITEMS YOU WILL NEED
Clear plastic 2 liter soda bottle
Air hose to connect reactor to skimmer
Soda Lime media
Egg-Crate, zip-ties
For my reactor I simply used a 2 Liter CLEAR plastic soda bottle. Having a clear bottle is important because the Soda Lime media is color changing and turns from white to purple as it exhausts. Clean the 2L bottle and drill 20-30 small holes in the bottom of it. The holes should be quite small to prevent the media from falling out. 1/16 or 5/64 works just fine. There is no science to this, so drill as many holes as you like, but they should be distributed evenly around the bottom of the bottle and should not be restrictive if you try to breathe through the bottle.
I built a small shelf out of egg-crate to allow unrestricted airflow through the bottom of the bottle-reactor. Again, not rocket science, just something to get the bottle up off the floor.
To run the air intake, drill a hole in the cap of the bottle sized to fit the air hose snugly.
Add Soda Lime media to the reactor and connect it up! It's literally that simple.
The media is DRY and simply filters the skimmer AIR intake. No water goes through the media and it should not get wet.
I personally like to use just a couple cups of media. Maybe 2-3" of media in the reactor. As it absorbs CO2, it will change color from white to a slight purple. The color change is not real dramatic so pay attention to it. Once it exhausts, as noticed through color change or lowered pH, replace the media. Soda Lime is not a hazardous material and can be disposed of in the household garbage.
You can adjust the amount of media to suit your needs. However, you should know that if the Soda Lime sits long enough after exhaustion, it will release the captured CO2, so it is possible to have so much media in a reactor that the lower portion reaches saturation and before it is replaced, it releases its CO2 which would then be absorbed by the top media thus reducing the longevity of the media.
Probably the best thing about this reactor/solution is that there is no real measuring/tweaking/etc to it. You're not adding anything to your tank. It's pretty much impossible to harm your tank using this reactor.
Soda Lime is available at your local AIR GAS (http://www.airgas.com">www.airgas.com</a>) which is a company that provides industrial & medical gasses & materials. You will have to call ahead to order the pail of Soda Lime as it's not usually stocked.
Here's a picture of my reactor:
[IMG]http://www.cbr600rr.com/reef/60_cube/100710/100710_3.jpg alt="" />
I showed this off at the reef club meeting this last week, and promised I'd do a bit of a write up on it, so here goes.
My idea was a CO2 scrubber.
What is a CO2 scrubber?
Good question! A CO2 scrubber is simply a small external DRY reactor which holds media that extracts excess CO2 from the ambient air.
Why use a CO2 scrubber?
The primary benefit of a CO2 scrubber is a higher pH in the tank.
How does it work?
The CO2 scrubber is simply a reactor holding media called SODA LIME (which is mainly comprised of calcium hydroxide, yep, that same pickling lime you use/see in kalkwasser - yet in a different media format). Soda Lime is commonly used in medical equipment and re-breathers for divers or firemen, and is a granular media which absorbs CO2 from air as it is drawn (or forced) through the media.
Details
There are many causes for low pH in tanks, and the cause we are combatting here is high CO2 levels in the ambient air which gets introduced into the tank through our skimmer air intakes or even through water trickling which breaks the surface tension.
In the Jack Kent presentation at the ARC meeting on 7/28/12, he stated that homes can have a CO2 concentration of 1000-5000ppm in the air versus something like 200ppm in fresh outside air. That CO2 gets introduced to the tank through your skimmer air intake or as mentioned above, any trickling water, etc. And this can (and does) affect your pH, lowering it.
The CO2 in your house comes from may places, mainly people & pets. The issue is that without extreme ventilation it has no place to go and will build up to levels much higher than that of outside air.
One way of combatting this is leaving a window open, or running skimmer intake lines to the outside of your house. The issue with those solutions is that it's not always safe or comfortable to leave windows open, and running a skimmer line outside gives you the risk of dirt, dust, pollen, insects, pollutants or possibly pesticides being introduced to your tank. The CO2 scrubber sits in your house and provides the same function for minimal cost.
You can buy commercially available reactors & media from reef stores for around $100 for the initial setup and then $50 for a small amount of media, but this DIY will run under $100 and give you enough media for a year or more.
ITEMS YOU WILL NEED
Clear plastic 2 liter soda bottle
Air hose to connect reactor to skimmer
Soda Lime media
Egg-Crate, zip-ties
For my reactor I simply used a 2 Liter CLEAR plastic soda bottle. Having a clear bottle is important because the Soda Lime media is color changing and turns from white to purple as it exhausts. Clean the 2L bottle and drill 20-30 small holes in the bottom of it. The holes should be quite small to prevent the media from falling out. 1/16 or 5/64 works just fine. There is no science to this, so drill as many holes as you like, but they should be distributed evenly around the bottom of the bottle and should not be restrictive if you try to breathe through the bottle.
I built a small shelf out of egg-crate to allow unrestricted airflow through the bottom of the bottle-reactor. Again, not rocket science, just something to get the bottle up off the floor.
To run the air intake, drill a hole in the cap of the bottle sized to fit the air hose snugly.
Add Soda Lime media to the reactor and connect it up! It's literally that simple.
The media is DRY and simply filters the skimmer AIR intake. No water goes through the media and it should not get wet.
I personally like to use just a couple cups of media. Maybe 2-3" of media in the reactor. As it absorbs CO2, it will change color from white to a slight purple. The color change is not real dramatic so pay attention to it. Once it exhausts, as noticed through color change or lowered pH, replace the media. Soda Lime is not a hazardous material and can be disposed of in the household garbage.
You can adjust the amount of media to suit your needs. However, you should know that if the Soda Lime sits long enough after exhaustion, it will release the captured CO2, so it is possible to have so much media in a reactor that the lower portion reaches saturation and before it is replaced, it releases its CO2 which would then be absorbed by the top media thus reducing the longevity of the media.
Probably the best thing about this reactor/solution is that there is no real measuring/tweaking/etc to it. You're not adding anything to your tank. It's pretty much impossible to harm your tank using this reactor.
Soda Lime is available at your local AIR GAS (http://www.airgas.com">www.airgas.com</a>) which is a company that provides industrial & medical gasses & materials. You will have to call ahead to order the pail of Soda Lime as it's not usually stocked.
Here's a picture of my reactor:
[IMG]http://www.cbr600rr.com/reef/60_cube/100710/100710_3.jpg alt="" />
