CO2 Scrubber having little to no effect on PH

[Randy Holmes-Farley Verified Community Expert]

I would have thought pulling air through the collection cup would mostly negate the need of a CO2 scrubber since you are using 'recycled' air. I do it on my mega skimmer primarily to prevent the mazzei injectors from getting clogged with salt creep.

Prevent the need? What do you mean? How does just recycling skimmer air remove CO2?

 

[The Opinionated Reefer]

Well, its did absolutely nothing to raise my ph today. What a waste of money!

Is there a way to work out how much fully saturated kalkwasser i would need to add over a 12 hr period to keep the ph raised by 0.2?

I was thinking i could maybe dose kalk every 30m throughout the lights off period. Not using it to maintain alk and calcium but just for ph increase and this would have the side effect of lowering my daily consumption of carbocalcium a bit.

Tank is a reefer 350 so somewhere between 300 and 350L of water in it.

 

[ca1ore]

Prevent the need? What do you mean? How does just recycling skimmer air remove CO2?

Was simply speculating that if one is running a skimmer with recycled air, the initial amount of CO2 in that air would be quickly removed. But that would mean the skimmer would be running as a closed system ....which it’s not, so never mind. I’m going to go with: on my system neither a fresh air line nor scrubber makes a material difference to pH ... and introduces additional inconveniences so I don’t bother.

 

[Lizdoesreef]

It's that way because it's re-circulating. This increases the life of the media because air that was already scrubbed is being sucked in again

 

[gfd71]

I wasn’t seeing anything until I removed the tubing for the inlet of the reactor. Once I did that I was getting increase of .2

also put your finger over the inlet for a second or two and remove to see if you hear a rush of air making sure you’re getting air going through the media

 

[adrianr514]

If there’s little or no CO2 in your water to begin with then a CO2 scrubber will not have any or very little effect.

the best way to gauge this is to open a window close to the tank. If with the window open your pH rises then CO2 is playing a factor. If not then you’re just wasting your money.

Also if you don’t want to run a CO2 scrubber but you do have a CO2 issue then running the airline outside works great as well.

 

[The Opinionated Reefer]

I think the issue is that the skimmer is not pulling enough air to complete with the gas exchange for the display. If I use an air pump to force air into the skimmer at an increased rate it seems to work. Looking like I need a more powerful skimmer.

 

[Randy Holmes-Farley Verified Community Expert]

If there’s little or no CO2 in your water to begin with then a CO2 scrubber will not have any or very little effect.

What???

If there is little to no CO2, the pH will be very high and there would be no reason to use a scrubber.

it is impossible to have low pH and not have excess CO2, unless your alkalinity is very low. To have pH 7.8 with normal CO2 (not zero) will require alkalinity below 4 dKH.

 

[adrianr514]

What???

If there is little to no CO2, the pH will be very high and there would be no reason to use a scrubber.

it is impossible to have low pH and not have excess CO2, unless your alkalinity is very low. To have pH 7.8 with normal CO2 (not zero) will require alkalinity below 4 dKH.

If a CO2 scrubber isn’t scrubbing or depleting CO2 media especially in a Recirc application the. It would indicate low to no CO2 would it not?

I’m obviously not the PHD here but that’s what I’ve always been told and know. To be true. How else would you explain that or opening windows and having no effect on pH?

 

[Randy Holmes-Farley Verified Community Expert]

If a CO2 scrubber isn’t scrubbing or depleting CO2 media especially in a Recirc application the. It would indicate low to no CO2 would it not?

I’m obviously not the PHD here but that’s what I’ve always been told and know. To be true. How else would you explain that or opening windows and having no effect on pH?

No, it would not, unless you are implying that the pH is not really low and is a measurement issue.

There is an exact mathematical relationship between CO2 in the water, carbonate alkalinity, and pH. Know any two and you can calculate the third.

If the alkalinity of seawater is at least 6 dKH, and the pH is 8.0 or less, there must be elevated CO2 in the water. How much it is elevated shows in the pH. Every drop of 0.3 pH units is about a doubling of the CO2 in the water.

Lack of substantial effect from a properly set up scrubber is because it is fighting against aeration with high CO2 air in other ways (like the tank top), or from CO2 added by tank organisms. Lack of effect of sufficiently open windows (aside from measurement error) is due to inadequate aeration, not excess CO2 in the air itself.

I show how to diagnose whether you have inadequate aeration (less common) or have elevated CO2 in your home air in this article:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

from it:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

 

[The Opinionated Reefer]

I actually tried using an air pump to pump air through the CO2 scrubber into an airstone in my sump. It worked great I was up at 8.36 ph. But the airstone causes to much of a spray in my sump and would coat everything with salt spray. Always a downside lol

 

[((FORDTECH))]

Might be more efficient (or not, not clear to me, depends on many factors) , but it eliminates one of the most useful aspects of skimmers, IMO, which is oxygenation at night. For that reason, I would not do it.

Of the 3 what do you think is best place to hook inlet of co2 scrubber ? Recirculate style to lid of skimmer, to fresh air line going outside, or inside house next to skimmer in the high co2 area?

 

[((FORDTECH))]

No, it would not, unless you are implying that the pH is not really low and is a measurement issue.

There is an exact mathematical relationship between CO2 in the water, carbonate alkalinity, and pH. Know any two and you can calculate the third.

If the alkalinity of seawater is at least 6 dKH, and the pH is 8.0 or less, there must be elevated CO2 in the water. How much it is elevated shows in the pH. Every drop of 0.3 pH units is about a doubling of the CO2 in the water.

Lack of substantial effect from a properly set up scrubber is because it is fighting against aeration with high CO2 air in other ways (like the tank top), or from CO2 added by tank organisms. Lack of effect of sufficiently open windows (aside from measurement error) is due to inadequate aeration, not excess CO2 in the air itself.

I show how to diagnose whether you have inadequate aeration (less common) or have elevated CO2 in your home air in this article:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

from it:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

The reason I ask this question above is because I have a large 1 1/2 inch pvc line ran outside for my skimmer which works great during winter but for summer with ac on ph is much lower and I was looking to try to help ph during summer with a Brs co2 reactor and wanted to know best setup since I already have access to large line going outside should that be used to feed co2 reactor or feed from skimmer lid or from basement where skimmer is at where the co2 is high ? Thanks for any help you can give me