The Co2 up and down teeter totter

[Scorpius]

Oh what joy it is to have my a/c on for a few days and then be able to have my windows open again.

I've found that as Co2 goes up my ph lowers, raising my alkalinity.
When the windows are open Co2 levels lower and so does my alkalinity.
So frustrating to deal with this. I have a fresh air line ran outside feeding my skimmer which helps, but isn't an end all be all.

 

[chipmunkofdoom2]

I'm suspecting that your alkalinity changes are due to the way corals calcify at higher and lower pH levels. It could be that you see higher carbonate alkalinity with the windows closed (high CO2, low pH) because it's harder for corals to calcify at a lower pH. When corals aren't calcifying, they aren't using carbonate, and your alkalinity levels could rise as a result (especially if you dose to maintain carbonate alkalinity). With the windows open (low CO2, high pH) corals are able to calcify again. This in turn lowers your carbonate alkalinity as corals pull calcium and carbonate out of the water to build their skeleton.

I started feeding my skimmer with outside air as well, and I was also unhappy with the results. I added an air pump, which also pulls outside air, and my pH has gone up even further. During the day my pH peaks just over 8.2. Before pulling outside air, my pH was very low, and used to dip below 7.7 at night.

 

[Scorpius]

I'm suspecting that your alkalinity changes are due to the way corals calcify at higher and lower pH levels. It could be that you see higher carbonate alkalinity with the windows closed (high CO2, low pH) because it's harder for corals to calcify at a lower pH. When corals aren't calcifying, they aren't using carbonate, and your alkalinity levels could rise as a result (especially if you dose to maintain carbonate alkalinity). With the windows open (low CO2, high pH) corals are able to calcify again. This in turn lowers your carbonate alkalinity as corals pull calcium and carbonate out of the water to build their skeleton.

I started feeding my skimmer with outside air as well, and I was also unhappy with the results. I added an air pump, which also pulls outside air, and my pH has gone up even further. During the day my pH peaks just over 8.2. Before pulling outside air, my pH was very low, and used to dip below 7.7 at night.

I'm looking at adding an air pump. Just gotta figure out how to tap into the air line I have run through the wall already.

How did you setup your air pump? Most air pumps don't have a barbed fitting on the air intake section. Did you put the air pump outside and run the airline inside?

 

[bubbaque]

Which air pump do you use?

I'm suspecting that your alkalinity changes are due to the way corals calcify at higher and lower pH levels. It could be that you see higher carbonate alkalinity with the windows closed (high CO2, low pH) because it's harder for corals to calcify at a lower pH. When corals aren't calcifying, they aren't using carbonate, and your alkalinity levels could rise as a result (especially if you dose to maintain carbonate alkalinity). With the windows open (low CO2, high pH) corals are able to calcify again. This in turn lowers your carbonate alkalinity as corals pull calcium and carbonate out of the water to build their skeleton.

I started feeding my skimmer with outside air as well, and I was also unhappy with the results. I added an air pump, which also pulls outside air, and my pH has gone up even further. During the day my pH peaks just over 8.2. Before pulling outside air, my pH was very low, and used to dip below 7.7 at night.

 

[chipmunkofdoom2]

I'm looking at adding an air pump. Just gotta figure out how to tap into the air line I have run through the wall already.

How did you setup your air pump? Most air pumps don't have a barbed fitting on the air intake section. Did you put the air pump outside and run the airline inside?

I used a sort of manifold to attach multiple devices to a single line from the outside. The single air hose from the outside gets split off to two different outputs, one to my skimmer and one to my air pump:



The air pump was a bit hacky, because as you mentioned it doesn't have an input barb. But it works, and the air pump is inside my house, which was important for me. I used a run-of-the-mill Whisper air pump from Petco and built an enclosure for it.



I bought a $7 vacuum seal food container from TJ Maxx and put the air pump inside.



I used a simple bulkhead and hose barb to make sure the air in the container was coming from the outdoors.



I drilled holes for the air hose output and for the extension cord so I could power the pump from inside the container.



I used hot glue to seal the holes to ensure most of the air in the container was coming from the air manifold, and thus, the outdoors (not the best sealant, but it works for now). The air pump takes air from the container. As the air is moved from the container, it is replaced by air from the outdoors through the bulkhead and manifold. The result is the air pump moves outside air into the tank.

I bought a cheap 12v diaphragm pump off Ebay with the intent of replacing my DIY creation, but I haven't had a chance to wire it up and get the tubing required to hook it up. The DIY air pump enclosure has been working so well that there hasn't been much incentive to change it.

Including @bubbaque in case you are not subscribed to the thread.

 

[bubbaque]

Thanks for taking the time to post your setup. I would just think the air pump wouldn't add anything extra that the big skimmer motor is already doing. I was curious if you had some high power air pump but it looks just like a normal one. I have a co2 scrubber coming tomorrow so I hope that make a difference beyond the airline hose to the outside that I currently use, if not I might add the air pump also as it seemed to work for you.

 

[Randy Holmes-Farley Verified Community Expert]

Oh what joy it is to have my a/c on for a few days and then be able to have my windows open again.

I've found that as Co2 goes up my ph lowers, raising my alkalinity.
When the windows are open Co2 levels lower and so does my alkalinity.
So frustrating to deal with this. I have a fresh air line ran outside feeding my skimmer which helps, but isn't an end all be all.

CO2 and pH do not directly impact alkalinity, but lower pH may reduce the growth rate of some calcifying organisms.

 

[chipmunkofdoom2]

Thanks for taking the time to post your setup. I would just think the air pump wouldn't add anything extra that the big skimmer motor is already doing. I was curious if you had some high power air pump but it looks just like a normal one. I have a co2 scrubber coming tomorrow so I hope that make a difference beyond the airline hose to the outside that I currently use, if not I might add the air pump also as it seemed to work for you.

I suppose it all depends upon the size of your skimmer. If you have a huge skimmer that's pulling a significant amount of air, it's possible that adding the air pump might not do anything. However, it's my understanding that the small bubbles produced by protein skimmers are not ideal for gas exchange. My experience seems to corroborate this. I started off by only running my skimmer to the outside, then added the air pump later. I saw a marked increase in pH after adding the air pump. I don't use an air stone on the pump or anything, the air just billows huge bubbles into my sump. I think the sheer volume of air is what makes the difference.

The air pump was sort of my last ditch effort before implementing a CO2 scrubber. But, after adding the air pump, my pH is usually between 8.1 (night) and 8.2 (day). So, I haven't needed the scrubber.

 

[Scorpius]

I might just go with the large Koi pond outdoor air pumps they make. Have it outside and run airline inside. Those Koi pond aur pumps put out a ton of air.

 

[Scorpius]

CO2 and pH do not directly impact alkalinity, but lower pH may reduce the growth rate of some calcifying organisms.

I realize this now. Thank you.

 

[Randy Holmes-Farley Verified Community Expert]

I suppose it all depends upon the size of your skimmer. If you have a huge skimmer that's pulling a significant amount of air, it's possible that adding the air pump might not do anything. However, it's my understanding that the small bubbles produced by protein skimmers are not ideal for gas exchange. My experience seems to corroborate this. I started off by only running my skimmer to the outside, then added the air pump later. I saw a marked increase in pH after adding the air pump. I don't use an air stone on the pump or anything, the air just billows huge bubbles into my sump. I think the sheer volume of air is what makes the difference.

The air pump was sort of my last ditch effort before implementing a CO2 scrubber. But, after adding the air pump, my pH is usually between 8.1 (night) and 8.2 (day). So, I haven't needed the scrubber.

I disagree. If skimmers were not good at gas exchange relative to the tank top, a CO2 scrubber on a skimmer inlet wouldn't be useful in raising pH that is caused by elevated home CO2 levels. But it is.

Smaller bubbles are better for gas exchange than larger bubbles of the same air volume because they have higher surface area. Obviously, more air is better however you do it.

 

[Randy Holmes-Farley Verified Community Expert]

I might just go with the large Koi pond outdoor air pumps they make. Have it outside and run airline inside. Those Koi pond aur pumps put out a ton of air.

Where are you going to send the air to?

 

[chipmunkofdoom2]

I disagree. If skimmers were not good at gas exchange relative to the tank top, a CO2 scrubber on a skimmer inlet wouldn't be useful in raising pH that is caused by elevated home CO2 levels. But it is.

Smaller bubbles are better for gas exchange than larger bubbles of the same air volume because they have higher surface area. Obviously, more air is better however you do it.

Understood, thanks for the info. I suppose my skimmer is just not pulling that much air, and that the additional air from the pump is significant enough to affect pH.

I do, however, see a greater pH elevating effect when I don't use an air stone on the air pump. Could it be that I just have a weak air pump? I suppose that if the air stone restricted air flow and produced fewer bubbles, even though they're more efficient, they may not have as great an affect on the pH if there is less flow overall?

 

[Scorpius]

Where are you going to send the air to?

I bought this. Comes with an air stone, air line, check valves, and t-fitting. I'll put the air stone in my sump. http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=28232

I already have a whole drilled through the side of my house, for my skimmer's air line, so all I'll have to do is notch an area out for the air pump airline to get inside the house.

Don't know if this will help in my case, but for $50 it's worth a shot.

 

[Randy Holmes-Farley Verified Community Expert]

It might well help. The main problem with airstones is salt spray.

 

[Scorpius]

It might well help. The main problem with airstones is salt spray.

I should be able to strategically place it to avoid any salt spray making it out of the sump and all over the insides of the sides of the sump.

 

[Scorpius]

It's been a few days and I'm seeing my ph in the morning before my lights come on around 7.7ish instead of 7.4ish ph. I'm using Salifert's older test kit without the updated color chart so I don't know how accurate my results are.

 

[bubbaque]

I was using salifert and it was reading way lower than my ph probe. I ended up buying a different brand ph test and it was on par with ph probe. I threw the salifert away. I love all their test but ph.

 

[Scorpius]

I was using salifert and it was reading way lower than my ph probe. I ended up buying a different brand ph test and it was on par with ph probe. I threw the salifert away. I love all their test but ph.

and the ph test kit you use is?

 

[Scorpius]

never mind bubbaque I ordered this

http://www.drsfostersmith.com/Product/prod_display.cfm?pcatid=24733