Growing plants to lower Co2 in the home.

[Scott.h]

So I’ve been monitoring my actual Co2 levels in my fish room. My fish room is 23’x11’x7.5 ceiling.
I’m in Michigan where typically I leave the fish room window cracked most all the time. In Michigan this is the time of year where it starts dipping down below freezing at night. Obviously this makes my energy bill higher and heaters work harder.

What I’ve noticed is even though the fish room isn’t air tight, and has a 6” breather duct going into my attic, how quickly the co2 rises in the room just by me working in there (breathing) with the door shut. Or the furnace running. Typical co2 levels with the windows open in my house are in the low 500 range. With the window closed and me in here it can jump over 650 in less then an hour. When the furnace kicks on 800. Easy. Obviously this directly affects my tanks ph. I also have a gas fire place upstairs, as this is basically prohibited of use, as I can watch the ph litterly drop in my tanks within minutes.

So my question is this. Plants love to absorb co2. Has anyone tried having indoor plants as a method to absorb co2 naturally inside of a house?

 

[Rubblereefer]

You’d need a lot of fast growing plants under strong light but I think it could work or at least help. Maybe you should set up a vivarium and worst case if it has no effect at least it’ll be a cool addition to your fish room.

 

[sawdonkey]

Your observations are similar to mine. The presence of humans almost immediately impacts PH. I got a CO2 scrubber when my mice was home for maternity leave. Now I have a unmaintainable goal of 8.3, which is hard to maintain.....but ya gotta have goals, or this whole thing gets boring, right?

don’t even ask about turning on the ventless gas fireplace!

 

[Brian_68]

So I’ve been monitoring my actual Co2 levels in my fish room. My fish room is 23’x11’x7.5 ceiling.
I’m in Michigan where typically I leave the fish room window cracked most all the time. In Michigan this is the time of year where it starts dipping down below freezing at night. Obviously this makes my energy bill higher and heaters work harder.

What I’ve noticed is even though the fish room isn’t air tight, and has a 6” breather duct going into my attic, how quickly the co2 rises in the room just by me working in there (breathing) with the door shut. Or the furnace running. Typical co2 levels with the windows open in my house are in the low 500 range. With the window closed and me in here it can jump over 650 in less then an hour. When the furnace kicks on 800. Easy. Obviously this directly affects my tanks ph. I also have a gas fire place upstairs, as this is basically prohibited of use, as I can watch the ph litterly drop in my tanks within minutes.

So my question is this. Plants love to absorb co2. Has anyone tried having indoor plants as a method to absorb co2 naturally inside of a house?

Plants release a lot of the CO2 at night thru respiration that they took in during the day while only a portion is fixed in carbon. Unless you have a large greenhouse you would most likely see no impact.

 

[adadwa]

If you already have a 6" duct running to your attic, why not run a pipe or tube inside the duct to the attic and connect it to your skimmer to supply fresh air to it? CO2 being heavier than air will not travel up the duct to the attic to any appreciable extent.

 

[Brian_68]

So I’ve been monitoring my actual Co2 levels in my fish room. My fish room is 23’x11’x7.5 ceiling.
I’m in Michigan where typically I leave the fish room window cracked most all the time. In Michigan this is the time of year where it starts dipping down below freezing at night. Obviously this makes my energy bill higher and heaters work harder.

What I’ve noticed is even though the fish room isn’t air tight, and has a 6” breather duct going into my attic, how quickly the co2 rises in the room just by me working in there (breathing) with the door shut. Or the furnace running. Typical co2 levels with the windows open in my house are in the low 500 range. With the window closed and me in here it can jump over 650 in less then an hour. When the furnace kicks on 800. Easy. Obviously this directly affects my tanks ph. I also have a gas fire place upstairs, as this is basically prohibited of use, as I can watch the ph litterly drop in my tanks within minutes.

So my question is this. Plants love to absorb co2. Has anyone tried having indoor plants as a method to absorb co2 naturally inside of a house?

When it is cold outside you will have warm air running up the pipe and out the attic. True CO2 is heavier than air but will only settle to any degree if the air is completely still and a house is not.

 

[adadwa]

When it is cold outside you will have warm air running up the pipe and out the attic. True CO2 is heavier than air but will only settle to any degree if the air is completely still and a house is not.

There should be plenty of air in the attic to sufficiently dilute any CO2 going up the duct making the air coming back down have much less CO2 in it. Shouldn't cost much to give it a try.

 

[EmdeReef]

the amount of CO2 taken by plants will be in correlation to light, temperature, size of leaves, tissue type and growth rates, CO2 concentration, humidity and plant species. In other words don’t expect miracles unless you can control the environment.

In closed chamber experiments, some plants such as ficus, under intense light, and constant stable temperature have shown “meaningful” CO2 uptake. These were fairly large plants, in a small chamber and results usually normalized for respiration etc.

 

[Stoney]

Wouldn't it be more efficient to have a refugium with macro algae directly absorbing CO2 from the water? You could also partially seal the tank to limit CO2 absorption from the air. Would probably be more compact too compared to terrestrial plants.

 

[Scott.h]

If you already have a 6" duct running to your attic, why not run a pipe or tube inside the duct to the attic and connect it to your skimmer to supply fresh air to it? CO2 being heavier than air will not travel up the duct to the attic to any appreciable extent.

I tried that first. I seen no difference really. But I did run a 7/8” tube directly outside. It helps but not as much as it could. With the windows open in the house my ph is 8.2-8.3 by evening. If I were to shut the windows within 3-4 hours my ph would drop .2. Don’t get me wrong this isn’t hurting anything. Just experimenting.

 

[Scott.h]

Wouldn't it be more efficient to have a refugium with macro algae directly absorbing CO2 from the water? You could also partially seal the tank to limit CO2 absorption from the air. Would probably be more compact too compared to terrestrial plants.

I have a sump almost the size of my display, and the fuge is half that with a kessil h380. I’m sure this helps, but the results could be better.

 

[Scott.h]

the amount of CO2 taken by plants will be in correlation to light, temperature, size of leaves, tissue type and growth rates, CO2 concentration, humidity and plant species. In other words don’t expect miracles unless you can control the environment.

In closed chamber experiments, some plants such as ficus, under intense light, and constant stable temperature have shown “meaningful” CO2 uptake. These were fairly large plants, in a small chamber and results usually normalized for respiration etc.

Good to know. It is a fairly controlled room. With good lighting (4000 par full spectrum)

 

[Dkeller_nc]

While adding plants to your fishroom may well be a nice thing to consider for aesthetic reasons, it's unfortunately not going to get you to your goal. As others stated, plants absorb CO2 during the photoperiod and release it at night, with a slight positive uptake over the 24hr cycle that represents the carbon incorporated into the plant structure as it grows.

One can, of course, choose very fast-growing plants like grasses and reverse the photoperiod cycle for the terrestrial plants with respect to the reef tank, but that won't help much with 24-hr furnace use in a cold climate.

Personally, if I were in your situation I'd consider a fresh-air heat-recovery makeup system. Whole house units can get a bit pricey, but a smaller unit is fairly reasonable, like this one.

 

[Scott.h]

While adding plants to your fishroom may well be a nice thing to consider for aesthetic reasons, it's unfortunately not going to get you to your goal. As others stated, plants absorb CO2 during the photoperiod and release it at night, with a slight positive uptake over the 24hr cycle that represents the carbon incorporated into the plant structure as it grows.

One can, of course, choose very fast-growing plants like grasses and reverse the photoperiod cycle for the terrestrial plants with respect to the reef tank, but that won't help much with 24-hr furnace use in a cold climate.

Personally, if I were in your situation I'd consider a fresh-air heat-recovery makeup system. Whole house units can get a bit pricey, but a smaller unit is fairly reasonable, like this one.

I’ve read it takes two hours for plants to “go to sleep”. I’m wondering if plants emit co2 primarily during this time. I could feasibly put a small fresh air exchange unit to help with this time. But cost savings and wasting heat when it’s zero out.. blowing hot air out because it’s high in co2 would probably defeat the purpose of leaving the window cracked in the room all the time.
I wonder how many plants it would take to offset, out of curiosity. I’d almost have to take measurements from a greenhouse.

 

[Dkeller_nc]

I suspect this could be calculated relatively easily, but the overall effect would require you to pick the plants you'd want to grow and measure their growth rate by weight. One could then estimate the total carbon uptake based on the average carbon content of the plant biomass. Plants respire CO2 continuously throughout the night, so you'd likely want to illuminate the plants during the time that the reef tank lights were off. I suppose that could create some issues with the plant lights putting too much light into the reef tank during off-hours for the fish and other critters to go into their normal night mode, but that could be controlled by light-block curtains.

By the way - you won't be wasting much heat with a HRV (heat recovery ventilation) unit. That's the primary point - the units incorporate a heat exchanger so that the outgoing heated air warms the incoming cold air. The efficiency of these units for doing this heat exchange is typically published in the specifications.

 

[Stoney]

I have a sump almost the size of my display, and the fuge is half that with a kessil h380. I’m sure this helps, but the results could be better.

Just curious, how often/much are you harvesting from the fuge? Also if respiration during dark hours is an issue, caulerpa can be lit 24/7.

Seems like no matter what option you choose, you're gonna be spending significant money. Even if the terrestrial plants do work, itll probably add a few hundred watts to your power bill at the very least. I've got some indoor plants under 400 watts of LEDs in the same room as my main tank and it doesn't affect my pH. As someone mentioned above, maybe itd be easier to just spend the money on a CO2 scrubber. Might even come out cheaper than the other options if you recirculate the air through your skimmer.

 

[Mical]

Personally, if I were in your situation I'd consider a fresh-air heat-recovery makeup system. Whole house units can get a bit pricey, but a smaller unit is fairly reasonable, like this one.

I'm w/ "Dkeller" re: air exchangers and living in Minnesota I had same issues. Our new home has one of these https://www.venmar.ca/101-air-exchangers-s10-ervplus.html

But as many here say "don't chase #s" (unless it's affecting your tank)

 

[Mandelstam]

If it's only the tank you're worrying about maybe try a recirculating CO2 scrubber for your skimmer? BRS did a video on that earlier this summer.
If it often gets up in the 800 range I would start to look into it for my own and families sake. Those levels start to effect you too.

 

[KrisReef]

I've known growers who pumped CO2 into their plant room to increase yield but they were not living in the same room.

Great question & discussion points on this thread!

 

[Oldreefer44]

I had the same issue and have a bunch of large indoor plants very near my tank. Tried CO2 scrubber which eventually plugged up the venturi on my skimmer. I ran a 3/8 tube from the venture intake out under the window by putting a weather strip to fill the rest of the gap. Solved the problem.