human CO2 math

[BradB]

Suppose I produce 1kg of CO2 every 24 hours, live alone and never leave my 1600 square foot home with 8 foot ceilings. My home is approximately 362,455 liters, the air inside has a mass of approximately 469 kg. If I am replacing 1/469 of this mass's O2 with CO2, that raises average indoor atmospheric CO2 by 2132ppm every 24 hours. That seems really really high. Did I make a math mistake? Or is ventilation that important?

Related question - if I drop my indoor atmospheric CO2 from 1500ppm to 500ppm by ventilation, my pH should rise and my Alkalinity should drop. I've already asked about the math on that - short answer, it is complicated and I haven't worked it out yet. Is this drop in alkalinity significant - I don't mean will the swing bother Acropora, but do I need to consider this when testing? If my Alk drops from 10dHK to 8dHK just because I ventilated but I assume my corals are using more Carbonate and increase my 2-part dosing, I will be dosing too much. Or will the drop be negligible compared to what my corals use in 1 day?

Another related question. If I drop my indoor atmospheric CO2 from 1500ppm to 500ppm by ventilation, my pH should rise and my Alkalinity should drop over time - not immediately. Suppose I add enough Kalkwasser to raise my pH to 8.4 (over the whole system volume, not just in 1 spot) and it drops back to 8.2. Can I assume my tank water has equalized CO2 with my indoor atmosphere? Or at least that my pH will not go back up just because of reduced CO2?

 

[mrlavalamp]

While I cannot answer your math question, I have noticed that I have had to increase my alk dosing in the last 2 weeks because the weather here finally got nice enough to keep doors/windows open at night.

I was stable at 8.5 dkh for a month or so after tinkering with the daily dosing for a while. It dropped to 7 dkh (5 days between tests, so hard to say how fast it actually dropped). I have had to increase my daily dosing by 40 ml so far and I am just getting back above 8 now (almost a week later).

 

[BradB]

While I cannot answer your math question, I have noticed that I have had to increase my alk dosing in the last 2 weeks because the weather here finally got nice enough to keep doors/windows open at night.

I was stable at 8.5 dkh for a month or so after tinkering with the daily dosing for a while. It dropped to 7 dkh (5 days between tests, so hard to say how fast it actually dropped). I have had to increase my daily dosing by 40 ml so far and I am just getting back above 8 now (almost a week later).

There are several possible reasons. If your pH is higher, your growth should be better (especially if your pH was low to begin with) so your corals are actually pulling more carbonate from your water. Looking at your tank, does it appear your growth increased?

 

[mrlavalamp]

My pH hasn't changed, just about 8.15 every time I test, but I am using a salifert color matching test so acurracy is what it is.

Even before I started dosing alk (months ago), my ph was still 8.0 even when my alk was almost 6 so I dont pay much mind to it.

I have all soft/lps corals so skeletal growth is tough to judge in such a short time, and nothing seemed to be suffering during this time.

 

[arking_mark]

Suppose I produce 1kg of CO2 every 24 hours, live alone and never leave my 1600 square foot home with 8 foot ceilings. My home is approximately 362,455 liters, the air inside has a mass of approximately 469 kg. If I am replacing 1/469 of this mass's O2 with CO2, that raises average indoor atmospheric CO2 by 2132ppm every 24 hours. That seems really really high. Did I make a math mistake? Or is ventilation that important?

Related question - if I drop my indoor atmospheric CO2 from 1500ppm to 500ppm by ventilation, my pH should rise and my Alkalinity should drop. I've already asked about the math on that - short answer, it is complicated and I haven't worked it out yet. Is this drop in alkalinity significant - I don't mean will the swing bother Acropora, but do I need to consider this when testing? If my Alk drops from 10dHK to 8dHK just because I ventilated but I assume my corals are using more Carbonate and increase my 2-part dosing, I will be dosing too much. Or will the drop be negligible compared to what my corals use in 1 day?

Another related question. If I drop my indoor atmospheric CO2 from 1500ppm to 500ppm by ventilation, my pH should rise and my Alkalinity should drop over time - not immediately. Suppose I add enough Kalkwasser to raise my pH to 8.4 (over the whole system volume, not just in 1 spot) and it drops back to 8.2. Can I assume my tank water has equalized CO2 with my indoor atmosphere? Or at least that my pH will not go back up just because of reduced CO2?

To answer some of you questions...

1. The addition or subtraction of CO2 from your system doesn't impact Alkalinity.
2. Alkalinity consumption will go up with higher pH through increased abiotic precipitation and coral growth which is dependent on your particular tank.
3. Assuming 8dKH and 1500ppm CO2 (which is highly unlikely as this is in the unhealthy range for us humans with extended exposure) your pH in equilibrium would be 7.8 NBS. With 500ppm CO2, your pH would increase to 8.2 NBS in equilibrium.