CO2 scrubber???

skinz78 · Mar 7, 2011

I have been reading up on raising my PH and it seems a few reefkeepers use C02 scrubbers with success. So I am wondering what people who use them construct them out of and what chem's they use in them. Also where do you buy the chems? Please post some pic's of your scrubbers.

Sasquatch · Mar 7, 2011

don't they just scrub air? is it run on the skimmer? just read the wiki on c02 scrubbers and can't see how you could apply it, light me up Coach

skinz78 · Mar 7, 2011

From what I hear they go on the air intake of the skimmer.

Sasquatch · Mar 7, 2011

did a little search and other than some migik dust that changes color it just activated carbon, so build a tower and fill it up, you'd really have to watch clogging or you may flood your skimmer with the reduced air flow

skinz78 · Mar 8, 2011

Yeah I was wondering if carbon would work.

mdb_talon · Mar 8, 2011

Carbon did not work at all for me, and not all use carbon. As for mine i use a refillable one brs sells. Instead of buying the reills from them(expensive) i tried carbon(useless for me), then i switched to one of the chemicals they use in scuba rebreathers. Sorry cant remember the name right now, but buying in bulk from a dive shop it was very affordable. I change it once a month.

skinz78 · Mar 8, 2011

How much of a difference did you see when you started using it?

mdb_talon · Mar 8, 2011

Sorry and yes they attatch to skimmer and do not impact my skimmer at all, but i imagine with very large skimmers sucking a lot of air maybe it would.

mdb_talon · Mar 8, 2011

I saw about .3ph change. My low previously was around 7.8. Now my low is about 8.1 or 8.2. I stopped using for awhile to test and i slowly reverted back to 7.8 by morning ph(not the next morning it took several days) Strarted using again and within a couple weeks it was back up. It does seem to take a couple weeks to see large impact on my tanks. Also if you dont have a co2 problem it not really gonna help.

CJO · Mar 8, 2011

Sasquatch said:
did a little search and other than some migik dust that changes color it just activated carbon, so build a tower and fill it up, you'd really have to watch clogging or you may flood your skimmer with the reduced air flow

Carbon is used on some to prefilter the air that goes in (personally don't think it's needed), but the activated carbon does nothing for the CO2. I'll try to get a writeup done this week.

CJ

CalmSeasQuest · Mar 8, 2011

I've used a CO2 scrubber for about a year - It's worked perfectly delivering about a 0.20 pH increase. It's a simple media canister filled with a color changing version of soda lime (BRS handles both the scrubbers and media now.) You simply connect it to your skimmer airline intake (it also makes a great silencer.) My system is only about 50 gallons total and I've yet to have to replace the color changing media. It's effectiveness depends on how much CO2 is present in the air surrounding the tank. In my case, my tanks are in a rather small living room with a fireplace that gets lots of use.

I was concerned that since the addition of the CO2 scrubber, my pH was perhaps trending too high (8.3-8.45 in late afternoon.) I stumbled across a couple of interesting relationship charts that came in handy. The first shows the balanced relationship between Alk and Ca. The second chart shows naturally occurring CO2 levels in NSW.

Alk meq/L Alk dKH Calcium ppm
0------------0-----------360
0.5----------1.4---------370
1------------2.8---------380
1.5----------4.2---------390
2------------5.6---------400
2.5----------7---------410
3------------8.4---------420
3.5----------9.8---------430
4------------11.2---------440
4.5----------12.6---------450
5------------14---------460
5.5----------15.4---------470
6------------16.8---------480
6.5----------18.2---------490
7------------19.6---------500

Ratio CO2 For ASW compared to NSW
VALUE IN CHART IS COMPARED TO A VALUE OF 1 FOR nsw AT SEALEVEL, OR x:1

Total Alkalinity (AT)
(mEq/l) . . . 2.0 .. 2.5 .. 2.6 .. 3.0 .. 3.5 .. 4.0 .. 4.5 .. 5.0 ... 5.5 ... 6.0
(dKH) . . . . 5.6 .. 7.0 .. 7.3 .. 8.4 .. 9.8 . 11.2 . 12.4 . 14.0 . 15.4 . 16.8
pH __________________________________________________ _________
7.7---------3.0 .. 3.7 .. 3.9 .. 4.5 .. 5.3 .. 6.0 .. 6.8 ... 7.5 ... 8.3 ... 9.1
7.8---------2.3 .. 2.9 .. 3.0 .. 3.5 .. 4.1 .. 4.7 .. 5.3 ... 5.8 ... 6.4 ... 7.0
7.9---------1.8 .. 2.2 .. 2.3 .. 2.7 .. 3.1 .. 3.6 .. 4.0 ... 4.5 ... 5.0 ... 5.4
8.0---------1.3 .. 1.7 .. 1.8 .. 2.0 .. 2.4 .. 2.7 .. 3.1 ... 3.4 ... 3.8 ... 4.1
8.1---------1.0 .. 1.3 .. 1.3 .. 1.6 .. 1.8 .. 2.1 .. 2.3 ... 2.6 ... 2.9 ... 3.1
8.2---------0.8 .. 1.0 .. 1.0 .. 1.2 .. 1.4 .. 1.7 .. 1.8 ... 2.0 ... 2.2 ... 2.4
8.3---------0.6 .. 0.7 .. 0.7 .. 0.7 .. 1.0 .. 1.2 .. 1.3 ... 1.5 ... 1.6 ... 1.8
8.4---------0.4 .. 0.5 .. 0.5 .. O.6 .. 0.7 .. 0.9 .. 1.0 ... 1.1 ... 1.2 ... 1.3
8.5---------0.3 .. O.4 .. 0.4 .. 0.5 .. 0.5 .. 0.6 .. 0.7 ... 0.8 ... 0.9 ... 0.9
8.6---------0.2 .. 0.3 .. 0.3 .. 0.3 .. 0.4 .. 0.4 .. 0.5 ... 0.6 ... 0.6 ... 0.7
__________________________________________________ ____________

Based on this data, and how my tank seems to run, it seems levels of pH 8.35 (8.25-8.40 Diurnal), 11.2 dKH and 440 Ca are about optimal. Obviously these are just targets and will fluctuate daily.

beaslbob · Mar 8, 2011

IMHO and IME the most effective CO2 scrubber is the various algaes in the system.

my .02

Viva'sReef · Mar 8, 2011

Very interesting topic indeed....first time I heard about his was a day or two ago.

CalmSeasQuest · Mar 8, 2011

beaslbob said:
IMHO and IME the most effective CO2 scrubber is the various algaes in the system.

my .02

In principle; I agree - but in my case, even with a reverse lit sump full of Chaeto, I still had a problem supporting the diurnal pH swings due to the elevated CO2 levels in the room during the winter. Another effective solution is to dose Kalk overnight. I've since taken the CO2 scrubber offline as the Kalk dosing is very effective, but for those operating sans Kalk, I think the scrubber is a very easy, inexpensive and safe solution.

skinz78 · Mar 8, 2011

beaslbob said:
IMHO and IME the most effective CO2 scrubber is the various algaes in the system.

my .02

My phosphates are very low, I can't even get Chaeto to grow worth beans.

beaslbob · Mar 8, 2011

skinz78 said:
My phosphates are very low, I can't even get Chaeto to grow worth beans.

then that might explain why your pH is low also.

Get the chaeto growing and watch the pH climb.

mdb_talon · Mar 8, 2011

beaslbob said:
IMHO and IME the most effective CO2 scrubber is the various algaes in the system.

my .02

Might work perfectly well for some systems, but for others it does not. Especially those with a very air tight house, high ground co2 composition, many people/animals in an area, etc, etc. Also affects those with extreme temperatures much more. In the spring/fall I have very few issues with CO2 as the windows in the house are open occasionally. Winter and summer though the windows do not open at all for 3 to 4 months at a time. There are many reasons people may have an abundance of Co2 in a house. As for mine in my basement particularly the CO2 is high. My algaes are not going to grow faster with CO2 alone. I have a very healthy refugium with various alage, but I also have nitrates and phosphates undetectable but still high Co2 levels. For those of us in that situation it can be particularly helpful.