Reef nutrition

Club - Would a lender CO2 meter be a good addition?


Staff member
Regarding plants and CO2 levels indoors, it isn’t a myth, but quantity matters. If you want to offset the CO2 production of a 150 lbs person you are going to need a similar or even greater mass of actively respirating plant material (not counting soil/pot/etc). So yeah not just a decorative pothos in every room.

Here’s a fun rabbit-hole on the subject that estimates you’d need 700 houseplants to offset a person’s breathing:


Staff member
I like this idea of a borrowable CO2 meter for the club a lot.

CO2 concentration in the air around the tank is by far the most important determinant of pH in the tank, especially if you have good air exchange. I have pretty good pH but I’ve always been curious about how CO2 level (and pH) changes with various factors. What I’ve done to get a poor-man’s estimate of this is to run an air stone in a cup of water in the location I want to test for 15 min, then check the pH of the water. But if I could test CO2 directly, even better.

@svreef If you want to have the one you bought be a club borrow item that would be great, we or you could just make a thread with some basic rules like we have for other equipment. I can bring it up with the rest of the Board if you are interested in reimbursement (which I would completely support), you can PM me. If you are considering donating it, in my opinion it doesn’t need Board approval, just implementation. If you change your mind and would like to hang on to it, no biggie, just say so and I’ll support a proposal to buy another one for the club.
I’ll donate it and start a thread.


Supporting Member
So yeah not just a decorative pothos in every room.
Challenge accepted :D. I am trying to do something like this pic below. Even if it doesn’t impact co2 I like the greenery! Let’s say you can get enough plants to reduce the co2 a measurable amount, I wonder if there are diminishing returns as the co2 lowers and the plants have less co2 to absorb And therefore grow slower. Also like Mike said early on, depends on the plant. Then, what would be a good plant to promote co2 exchange?


Supporting Member
It really would be neat to see how much of a difference, or not, that plants make!

However, does anyone know at what point it makes a difference? I mean if your tank is in a room and the CO2 is 400, then you sit in the room for an hour and it's not 800 ... does that matter?
Or if indoor air is 600 and outdoors it's 400 ... is that enough to make a difference to the tank ph?

I'm guessing it' discussed in CO2 scrubber threads. I wish I had an easy way to get a line outside without poking holes in walls or floors! I mean I'd do it, but it would give Wifebane a much greater meaning.

I don't have a co2 meter, and this is a little extreme because of conditions... This was after 3 or so days of having the house closed up because of the smoke outside, and then opening the house and running the whole house fan when the air outside was cleaner.

Also, I believe the air coming out of a co2 scrubber is generally under 100
Screenshot_20200914-211923_APEX Fusion.jpg


Supporting Member
This is what happens when I’m bored. I stole this idea from someone on Facebook, so I can’t claim the idea as my own. If you can get a hold of an ASM (comes with PMK) and get an HVAC CO2 Ventilation Controller that has a 0-5V output (got one on eBay for $45), you can add CO2 monitoring to Apex Fusion.



Last edited:


Supporting Member
@RandyC could you post a pH compared to CO2?
I will eventually. Just wired it today so not much data yet. Plus I hooked it up to my garage tank first and that may just prove to be very boring as the CO2 level may just stay constant. I’ll eventually hook it up to my tank inside the house and that will probably more interesting and I’ll post that data when I get it.