Lowering Indoor CO2

[Jayhawk88]

I've discovered that my low pH problems are due to excessive indoor CO2. Do you know why it is that some homes have excessive CO2 and some don't? Is there something that I can do to lower the CO2 levels in my home?

[SI_rEEfer]

Look into installing an ERV.

[Jayhawk88]

OK. What does ERV stand for?

[Boomer]

This should explain it all

http://www.monolithic.com/gallery/equipment/erv/

[Randy Holmes-Farley]

Excess CO2 is mostly of a concern in new, air-tight homes where air from outside does not readily exchange through the home.

Lots of people around, and cooking with gas will both be big sources of CO2.

This article may help understand the issues:

Indoor CO2 Problems
http://www.advancedaquarist.com/issues/apr2002/short.htm

[Beverly]

We moved into a brand new condo last year. Airtight as heck :mad: Couldn't figure out why pH was so low in our tanks. Did a test aerating a glass of NSW for 10 minutes indoors, then a second glass outdoors. pH rose minimally indoors, but rose significantly outdoors (was winter at the time too).

Once we realized how much CO2 was in our abode, we decided to keep a window in each of our two bedrooms open an inch or so, and placed a fan in the hallway blowing air into the living/dining rooms where our tanks are situated. Improved pH as well as improved the quality of air for us humans :)

During the hot days of summer up here (Edmonton, Alberta), we run our AC only during the part of the day when it is hottest and have the windows open the rest of the time for air exchange. If there is little or no wind, we keep fans running to exchange the air.

[sharpexx`]

So for those of us in the South (Well more south then Canada) who can't leave the windows open...I assume the only short term solution (ERV takes time/money) is to does Kalk to raise the PH correct??

FYI...My PH runs at 7.8 with the windows closed (comes out of my RO/DI around 8.0)

Sean

[Hobster]

I think it was Randy who suggested that if your Skimmer allows to hook up some sort of airline tubing to draw air from outside.
In another thread, some folks also discontinued breathing inside:lol:

[Beverly]

Originally posted by sharpexx`
So for those of us in the South (Well more south then Canada) who can't leave the windows open

Why can't you leave your windows open for a few hours at a time in Indiana? BTW, in the western hemisphere, pretty much everything is south of Canada, excluding the anomoly of Alaska of course :D

[sharpexx`]

Beverly...The reason (in my case) 2 kids, 1 wife, too much humidity and heat. :rollface:

But seriously...it rains contstantly around this time of year and your house gets very sticky..the high levels of humidity cause all sorts of mold issues. We have entire neighborhoods out here with mold problems. :mad:

So need another option.

[Beverly]

sharpexx,

Yes, I have heard of mold problems in houses. It probably doesn't help to have water evaporating from your tanks either :( Sounds like a dehumidifier and an air exchange device would be of great help in your case. Kinda wish we had a dehumidfier just now as we've had two weeks of serious rain and it's pretty humid inside. Ah, maybe I'll wait a week and we'll be back to hot and dry weather :)

As for dripping kalk to raise pH, you could probably be successful to a certain degree with that method, but if high CO2 is the main problem that has to be addressed first. pH is dependent on the amount of buffer (or KH) in your system. KH should be between 8.5 and 11.

[Boomer]

I think it was Randy who suggested that if your Skimmer allows to hook up some sort of airline tubing to draw air from outside.

Yes, that will help but you are still left with the high room air, which will diffuse into the tank

pH is dependent on the amount of buffer (or KH) in your system

Actually it is dependant on the amount of Alk (buffer/KH) and CO2. Seawater is actually buffered better at a much lower or higher pH. i.e, 6 & 9. It is CO2 that makes the pH go up and down most of the time. CO2 has no effect on Alk and Alk has no effect on CO2. A high Alk can still have a low pH, due to CO2. If you "blow-off" the CO2 the Alk stays the same but the pH goes up.

As for dripping kalk to raise pH, you could probably be successful to a certain degree with that

This actually works quite well but some people do have a serious issue on high CO2. It certain dwellings it can be hard to get it out, unless you leave a window open or go to some extreme like a ERV

PS

Is this my Bev from Edmonton

[sharpexx`]

Thanks everyone..I tried dripping kalk yesterday as a test and the PH quickly came up (of course it went right back down to 7.88 within a few hours of stopping)...so I am going to start using it is my topoff all the time. I will monitor the Alk and other perams to make sure they don't get out of whack. And hope fall gets here soon so I can open the windows again.

Thanks everyone.

Sean

[Randy Holmes-Farley]

That sounds like a good plan.

Good luck!

[Beverly]

Originally posted by Boomer
Is this my Bev from Edmonton

Yes, Boomer, this is Beverly in Edmonton. How do you know me other than from the very few posts I make here?

[Boomer]

There was once a reefer named Beverly Wladyka
from Edmonton on our reef Newsgroup RAMR. She also had FW tanks so I thought this was you :D

[Beverly]

Originally posted by Boomer
There was once a reefer named Beverly Wladyka
from Edmonton on our reef Newsgroup RAMR. She also had FW tanks so I thought this was you :D

That's me :rollface: Have moved several times over the past 5 years. Lost interest in fw once we got into reefing. How the heck did you remember that weird last name????

Boomer, Boomer...... I think it's coming back to me now :cool: Is RAMR still on the go? I like the boards better than newsgroups because of all the pics we can post here.

[Boomer]

How the heck did you remember that weird last name????

The masterful power of Google and its search engine. Just went to the now owned Google newsgroups, to RAMR and typed in Beverly in the search.

http://www.google.com/

See where it says Groups, just start walkin', rec-->aquaria->marine-->.reef. Put a check mark in search in RAMR only and type in Beverly or Deflizard, Jimmy Chen, Craig Bingman, Deb Hartford and poof all your/there old posts will pop-up :D It was me, you were on that thread, that explained to Deb on how to raise Lemon Peels successfully. It was also me that explained the detailed chemistry of Chloramines to you and how the chorine is removed from the RO by reacting with the carbon prefilter :D

No, most of all the ones you know are all gone. I pop-in once in awhile as do a couple of others. My home for the last 3 years or so is here with Randy. We bought one of the old RAMR reefers a forum last year Teri Gallagher, Aka ReefLady along with Travis ( you don't know him), it is along story. I'm there also

http://www.reefsanctuary.com/

[Beverly]

Reading your signature really brings it back now, you old bomb tech, you :strange: ;) :D I seem to remember adressing you Boo for some reason.......

All the other names come back too. Deb's now on http://www.canreef.com/ (Canreef) as EmilyB. She's as batty as ever, maybe moreso ;) Don't know if she has all her lemon peels anymore, though. I'm there too as, well, me.

Small world, man, small, small world :cool:

[beaslbob]

Beverly:

Just an idea here. I had a daytime ph of around 7.4 or lower. that was with the aquarium pharm**** test kit. And had many problems when intorducing fish into the system. Upon adding macros the daytime ph went up and stayed at 8.2-8.4. If you are having an indoor co2 problem, seems like more plant life in your system could also remove the co2 regardless of the room co2.

Just a thought.

[ufans]

I was also wondering about the algae and plant idea. Does anyone know how much C02 a basic houseplant might consume?

[sharpexx`]

Beaslbob...I thought about that too...I plan to work on a redesigned Refugium this weekend so I can incorporate more macro algae into the system in the hope of lowering the CO2.

Keeps the great ideas coming - I am sure with enough of them we can come up with a good way to lower CO2 on any newer "well sealed" home.

Sean

[sharpexx`]

ufans...I don't know the exact amount...but I do know it is a double edged sword. When the sun is shining on the plants they consume CO2...but when shaded or at night they give off CO2.

Does anyone know the actual ratios?

[beaslbob]

Originally posted by sharpexx`
ufans...I don't know the exact amount...but I do know it is a double edged sword. When the sun is shining on the plants they consume CO2...but when shaded or at night they give off CO2.

Does anyone know the actual ratios?

Not sure about house plants but am sure of what happened in my tank. From my experience in a "closed" system if you do not have plant life to consume the CO2 (and release O2) from the animal life, you get high levels of CO2. From what I understand plants consume more CO2 then they release at night. After all that is what balances the animal respiration on planet earth.

I only more macros works as well on your system as it did on mine. Keep us posted.

[thackray]

Piping outside air to an air stone via an air pump would be the simplest of all solutions if it works.

This may not be true for all systems but in my case, the air provide by the air stone overpowered the effects of 1) diffusion from the local air and 2) a good skimmer running well.

It is a very simple system that would eliminate the need for leaving the windows open or expensive house modifications.

Constantly lit refugiums and kalkwasser dosing at night will also help.

Phil Thackray

[sharpexx`]

Phil....That would be a good idea if I can figure how to discreetly get the air line to the tank from the outside and make it look ok. I will work on it over the weekend and let everyone know what works out.

Sean

[Beverly]

Originally posted by thackray
Piping outside air to an air stone via an air pump would be the simplest of all solutions if it works.

It is a very simple system that would eliminate the need for leaving the windows open or expensive house modifications.

Would work great for the tank only, but what about the other O2 deprived inhabitants in the home? I'm supremely happy with my solution of the open windows. All the living things in our house benefit from the fresh air. This may not be everybody's solution, but it works well for two adult humans, our five finches in their indoor aviary, our juvie ball python, and of course our three reefs :cool:

[thackray]

Beverly,

The amount of CO2 in the atmosphere is extremely small. Normal air is 330ppm that’s 0.033%. Bad air (high CO2) is say 700ppm or 0.07%. The amount of oxygen in normal air is 20.947%. Because of the great discrepancy between O2 and CO2 levels, we can say that large changes in the CO2 levels can be caused by very small changes in the oxygen levels.

The O2 reduction needed to create the levels of CO2 increase that we are talking about would not be significant or noticeable.

There may be other reasons to keep your windows open but biological oxygen need is not one of them.

Phil Thackray

[Randy Holmes-Farley]

Using macroalgae can help, especially if you keep it lit most of the time. The effluent from the refugium runs roughly 0.1 pH unit higher than the inlet to it.

We've discussed CO2 scrubbers in the past (submarines use things likelt hem), but they can be expensive and complicated. They usually involve passing air over or through a high pH solution of some sort.

[Beverly]

Phil,

Thanks for giving us the interesting facts about CO2 and O2 in the atmosphere. However, we are talking about air tight homes and the accumulation of excess CO2 in them.

Here is a quote from an earlier post of mine:

Did a test aerating a glass of NSW for 10 minutes indoors, then a second glass outdoors. pH rose minimally indoors, but rose significantly outdoors (was winter at the time too).

I went back to my notes to find out exactly what the results from the experiment were:

Sunday morning:

- take 8 oz of NSW from partially covered bucket, aerate with air pump and air line indoors for 10 minutes

* beginning pH is 8.11
* after 10 minutes aeration pH is 8.11

- take 8 oz of NSW from the same partially covered bucket, aerate with air pump and air line outdoors for 10 minutes

* beginning pH is 8.11
* after 10 minutes aeration pH is 8.17

Sunday afternoon:

- open two bedroom windows about an inch each, add ocellating fan in hallway to push air into dining/living rooms where tanks and NSW bucket are

Monday morning:

- take 8 oz of NSW from the same partially covered bucket, aerate with air pump and air line indoors for 10 minutes

* beginning pH is 8.15
* after 10 minutes aeration pH is 8.22

From the above information, can you give me some kind of idea what CO2 levels in our airtight condo were before opening the windows?

TIA for your time and expertise.

[thackray]

Beverly,

I understand the CO2 elevation problem in tight new homes. The CO2 is produced principally from plant and animal respiration and combustion. In these processes O2 is consumed to produce the CO2. Perhaps I misunderstood, I though that you were worried that the O2 in the house was being depleted through the process of conversion in to CO2. My discussion was aimed at showing that CO2 levels can be significantly raised without a significant drop in O2 levels.

I earlier suggested that high CO2 levels in some tanks could be corrected by bringing outdoor air in through an air stone. This method does not correct the essential in-the-house high CO2 levels. I also hoped to reassure anyone wishing to try that method that there is no significant reduction of O2 levels in houses with CO2 increases that typically lower pH in aquariums.

However, it is certainly true that improperly ventilated combustion processes could significantly lower oxygen but in that case the CO2 would be vastly higher than the levels we are discussing here.

Sorry if I misunderstood the meaning of your post.

Phil Thackray

[Boomer]

Just wondering but did you guys look at Randy'spost and link

http://www.advancedaquarist.com/issues/apr2002/short.htm

[thackray]

Beverly,

I think Randy and Boomer have the equations that could answer your question on a spread sheet. To solve the problem however they will need the alkalinity measurement from the samples that you measured.

Phil Thackray

[Beverly]

Excellent article, Boo.

Phil,

Did not measure alkalinity of the NSW but assume it was about 9-11 dKH. The NSW had been aerating for 1-2 days in a partially covered pail before testing.

[Randy Holmes-Farley]

If it is just NSW, the alkalinity is probably more like 6-7 dKH. If you fully aerate that in your home (which may tank an hour or more for an airstone in a cup of water), then the pH at 8.2 suggests little excess CO2 (the exact value of which can be confirmend with outside air). A pH of 8.0 or less means a lot of excess CO2.

[jfinch]

I remember (vaguely... it's been a while) in high school chem class calculating how much CO2 was generated in breathing by doing a very simple test. This might work for checking a home for CO2 too.

Take a very dilute basic mixture. I'd start with something like 0.01 N OH- (this may need to be altered). Add a few drops of phenolphthalein indicator. This will turn the solution slightly pink. Now measure out a couple ml of this into a test tube. Add enough DI water to fill the tube half way or so. Now using as large a syringe as you can find, with airline hose attached to the end, go outside and bubble air through the mixture until the pink color disappears and the solution goes clear. Keep track of how many ml of air it takes (or how many syringe pulls). Now go inside near your tank and repeat the experiment. The ratio of air from inside to air outside will be the ratio of CO2 inside to outside. If you assume the outside is 350-400 uatm, then you can calculate your inside CO2 concentration. Then to see what pH your tank could equalibriate at you could go to CO2 Program (http://cdiac.esd.ornl.gov/oceans/co2rprt.html) and input that along with your total alkalinity and let it calculate the pH.

[thackray]

Jon,

Since the bubbles of air would pass through the solution to the atmosphere it seems that you are relying on the total surface area of all bubbles and the time they are in contact with the solution for CO2 transfer. This would require a repeatable bubble source mechanically located in the solution container. Perhaps an air stone would work but I think you would have to control the depression rate of the syringe. Does that sound right?

Did you notice in the article that Randy referenced in his first post in this string (I did read it Boomer) that he lists methodology and a simple chart listing pH changes and corresponding CO2 concentrations. The only limitation of this chart is that it was made at a fixed alkalinity (3.5meq/l). Using the program you referenced, a set of charts or graphs of pH versus CO2 at constant alkalinity could be generated and used in conjunction with the test method described in the article.

Phil Thackray

[jfinch]

:D I only listed that procedure because this topic pulled up a long lost memory (high school chem class). :lol: Yes there are problems with the procedure... an air stone would help.

FWIW, you can use that program to calculate the dissolved CO2 (actually it's partial pressure) by using your tank pH and alkalinity as inputs... that's the easiest way to do it! My basement has 1000 uatm CO2 according to that program.

[Jayhawk88]

Would aerating my aquarium with an oxygen tank lower the CO2?

[Randy Holmes-Farley]

Yes it would, if it is pure O2 and you aerated it enough.

[Jayhawk88]

Do you know where I could get a tank of 02? And do you know if it would be a cost effective way to deal with my pH problem?

You know, I really don't understand why we have such high indoor CO2 levels. Our house was built in 1976, and it doesn't seem very air tight. We did install a new air conditioner recently... do you think this could be a factor? However, it definitely seems that the low pH is caused by the indoor co2 levels. The pH in my tank tonight was 7.82. I took a cup of tank water and put it outside with an airstone. An hour later the pH was 8.2.

Thanks for your help.

[Randy Holmes-Farley]

A tank of pure O2 will be quite expensive, may not lower pH much since it will not be the only aeration present, and may actually be very dangerous. I was treating this as a theoretical question, not a practical answer to low pH.

Jayhawke88: did you try the same with inside air?

[Beverly]

Jayhawk88,

I would think an AC unit left on for days at a time would definitely be a factor. We have AC and have been using it the last few days during our current heat wave. High today will be 27C (81F), but it's about 19C (67F) outside right now (5 am). The air is so stuffy in our condo right now that I turned off the AC and opened all windows and balcony door. Got all the fans running pushing outside air inside. Feels and smells better already in just 15 mins. Will close windows and turn the AC back on when it heats up a bit, but really needed to replenish the O2 for us humans, never mind the tanks.

[Scuba Dog]

What about a bottle of breathing air used for airation for the tank...would that help raise the ph? I dont have any windows near the tank...and cant run a line from an other window to the tank my wife would go ape ....

[Randy Holmes-Farley]

You'd be trying to drive off CO2 with that air while all other forms of aeration (such as the surface of the tank and the skimmer) will be driving it back in from the home air. So I wouldn't expect that to be very effective.