CO2 Scrubbing: An Unexpected Journey Chasing Numbers

[Randy Holmes-Farley Verified Community Expert]

Which as I understand it the PH will rise not fall due to photosynthesizers consuming the CO2 not lowering it or am I missing something here?

The pH rises in the tank due to CO2 consumption, making it deficient in CO2 relative to the home air (most often, anyway), and in that situation, a skimmer aerating the water will tend to lower the pH back toward equilibrium with the home air by driving in more CO2. In other words, the pH would rise higher in the absence of a skimmer in that scenario.

 

[Randy Holmes-Farley Verified Community Expert]

Do you know if adding this CO2 scrubber would help lower my ORP? Currently my pH is right at 7.98 ORP is spiking to 460 to 465. Do you think this will help solve my issue? Thank you

ORP is NEVER "too high" unless you are adding oxidizers such as ozone or bleach. So there is never any reason to want to lower ORP unless you overdosed one of those.

 

[Ty Hamatake]

FWIW....

First great thread and a CO2 scrubber is a great option for many people that have low pH and can't drill a hole to the outside to draw in fresh air (or their fresh air isn't much better...).

I also run a CO2 scrubber and an ATS and limewater all working together to help my pH. The ATS helps the least amount of less then a pH of .1 but can be seen when it's taken offline. I used to run it 12 hours, 16 hours, and 18 hours mainly over the night hours but have gone full 24/7 with all the same impact on pH.

With out any intervention my pH is easily 7.8's and dipping to the 7.7's and much more so in the winters with the furnace and fireplace going and if more people are over breathing. I have a CO2 monitor and it's commonly well over 800 and into the 1000's

My primary means of increasing pH is my limewater dosing. I used to use limewater with my ATO but I found separating my ATO and limewater to help even more. The limewater dosing by itself is less then the evaporation rate but is consistently dosed. I have it dosing for 1 second every minute 24/7.

My next method of helping pH is my CO2 scrubber. I live in an area where I have no idea when pesticides or other chemicals are being sprayed around. I'm not going to pull in that air or rely on carbon. The CO2 scrubber has become almost just a necessity now for the Winters since splitting out my limewater dosing from the ATO making it more efficient.

No Intervention:
pH swings 7.7's to 7.9's

Limewater ATO by itself:
Sub 7.8 to ~8.0 swings daily with periodic spikes due to higher evap rates

Lime water ATO plus CO2 scrubber:
~8.0 to 8.3 swings daily with periodic spikes due to higher evap rates.

Lime water dosed separately under evaporation rate and NO CO2 scrubber:
~8.1-8.2 swings daily with no spikes due to increased evap rates.

Those were readings last fall. Since going through the Winter months
Lime water dosed separately under evaporation rate and NO CO2 scrubber:
~7.9-8.1 swings daily with no spikes due to increased evap rates

Limewater dosed separately under evap rate + CO2 scrubber
~8.0-8.2


If my pH was swinging a lot more then I'd look at boron additions but the swings seem fine to me.


As for the CO2 scrubber to make it more efficient I restrict the amount of air going through it. Also my new skimmer seems to be a lot more efficient at aeration then all my previous skimmers. Which I personally believe can be attributed to the injection method and the height of the skimmer.

For restricting I found full air draw from the skimmer just wastes the Sodalime with diminishing returns. So, I T off the skimmer's air line and put a valve on the air drawn from the CO2 scrubber. The other line off the T is not restricted at all so the skimmer is still getting it's full air draw.

Here's my setup with a CO2 scrubber and ozone (ozone isn't part of this and I have never seen any impact on pH with it.)
https://www.reef2reef.com/threads/mtc-mvx-skimmer-review.252436/page-4#post-3101922


And a follow up post on my belief in the injection and dwell time working together to make the most of the CO2 scrubber (which I could be entirely wrong about the injector thing but my results are positive.)
https://www.reef2reef.com/threads/mtc-mvx-skimmer-review.252436/page-9#post-3671848

Very interesting and great reply! I would like to eventually dose my limewater separate from my ATO, but the whole reason I am right now is because a doser is not really a possibility at the moment. I don't think my tank is utilizing the alk or ca fast enough to rely solely on the kalk for pH, something I just may have to try once my consumption picks up though!

I have a similar setup in regards to the air intake, just opposite of yours. The scrubber is attached by six feet of tubing so the air tends to completely bypass it and go straight through the open end, which is why I put on valve on it instead of the scrubber itself.

Thanks for the reply, if it definitely has me thinking of my next experiment!

 

[Sir Chris]

Also thanks for this. When I run my skinner idk if my O2 is clear enough here and think it is but for a person with really dirty air not just for the tanks sake for a O2 tank added 2 help keep the media from depleting so fast if fix my air... haha seriously. Thanks to everyone that took my idea and rolled with it and was highly respectful. Thanks.

 

[Richard baker]

I'm a little late to the conversation but I run a waterfall Ats and a fuge packed full of macro I've never noticed a big difference in ph since adding the Ats I run my lights on a reverse photo period 12 hours I had to add a CO2 scrubber to stabilize ph during the night sometimes it would get as low as 7.72 since adding the scrubber lowest I have seen at night is 7.86 which I can live with my tank is approaching 7 years old in September .

 

[Richard baker]

this is my ph

 

[Ty Hamatake]

this is my ph

Better late than never! With a tank that old, how long were you having problems with your pH? Once you got it up and stabilized did you notice any improvements? I ask because my tank is relatively young and am convinced that the higher and stable pH was key to finally seeing healthy and growing coral. It could've just been my tank finally hitting its stride, but you have more reference with an older system.

 

[justingraham]

So the media will last longer if it is wet?

I just added a co2 scrubber and the media lasted about 14 days

 

[Ty Hamatake]

So the media will last longer if it is wet?

I just added a co2 scrubber and the media lasted about 14 days

You don't want the media itself to be wet, but IME keeping it from completely drying out (somehow humidifying the air it's pulling in) will make it last longer. What brand are you using? I know that BRS suggests to add a small amount of RODI water to the housing before you insert the canister, but I don't know about other brands. The stuff I use now is designed for rebreather diving and whatnot, and is advertised as having "the correct moister content". I don't know how to interpret that exactly, but I'm guessing that keeping it somewhat moisturized increases its longevity.

 

[justingraham]

I am using cdx by tlf in a phosban 150 canister

 

[justingraham]

So ur muffler is a can filled with water that goes on the input of the media reactor
So something like this ?

 

[revhtree Verified Admin]

Ordered the BRS Scrubber with BRS media yesterday. I'll keep you updated!

 

[Ty Hamatake]

So ur muffler is a can filled with water that goes on the input of the media reactor
So something like this ?

Exactly like that. I use an old AcroPower bottle (500 ml) and it lasts about two weeks. As a note, it's not actually sucking water into the scrubbers, it's just pulling air through the water filled container. If you end up doing this I'd love to hear how it works out!

 

[Ty Hamatake]

Ordered the BRS Scrubber with BRS media yesterday. I'll keep you updated!

Oh man! I hope you get the results you're looking for. Are you going to be running just one scrubber or are you doing daisy chaining it?

 

[Richard baker]

Better late than never! With a tank that old, how long were you having problems with your pH? Once you got it up and stabilized did you notice any improvements? I ask because my tank is relatively young and am convinced that the higher and stable pH was key to finally seeing healthy and growing coral. It could've just been my tank finally hitting its stride, but you have more reference with an older system.

I actually have never tested ph until I got my apex which was back in February. I had older lights which was 150 watt mh and 96 watt PC . My coral did OK but not alot of growth and color was kinda bland .. In February I added two new gen 4 pros radions I got good color within a month in all my sps.. Now since I added the scrubber I've noticed what seems like increased growth in my montis and my chalice . It's only been a little over a month so I can't really be accurate in saying I've noticed alot of difference as of yet

 

[bubbaque]

If you closed the ball valve on the tee wouldn't your ph rise even higher? What is the purpose of the tee to increase the duration before changing the media?

 

[Ty Hamatake]

If you closed the ball valve on the tee wouldn't your ph rise even higher? What is the purpose of the tee to increase the duration before changing the media?

Yes and yes. I figured I'd rather have 8.1 for two weeks than 8.3 for less than one!

 

[bubbaque]

How much did you pay for shipping from the site you linked on the first page? I went to buy it but shipping is $46.

 

[Ty Hamatake]

How much did you pay for shipping from the site you linked on the first page? I went to buy it but shipping is $46.

That actually sounds about right. I don't remember exactly, but I think I paid around 120 for it. It is expensive, but still quite a bit better of a deal than BRS.

 

[bubbaque]

Does it work any better or last longer? I see on shopmedvet it's like $95 including shipping but it doesn't say anything about already having the correct moisture content.