CO2 meter use and data

[Tom Barr]

I'm redoing some CO2 meters for a client, I have the stationary model and also a portable model, so I'll be measuring some tanks out and about as well as my own.

I also have some controllers and will link them to the mV reading and assume the scale 20mV= 1ppm of CO2 and data log.

I have several methods for calibrating of the CO2 meters I plan on using with known standards.
Not cheap, but lots cheaper than these meters!!

The last test I did was very enlightening.
This time I'll double and triple check things and also calibrate with 3 different methods to ensure what my CO2 really is.

I have two CO2 meters, and new probes, new calibration s kits(Oxyguards, plus 2 of my own methods, one used a KH reference and pH with DI/RO water, another uses Gas at a known concentration of CO2(100ppm and then it'll be cut in 1/2).

Regards,
Tom Barr

 

[dutchy]

I'm very curious to know the results!!

regards,
dutchy

 

[Tom Barr]

Well, I've been thinking about this for some time. So I've got some plans to play around with them. I almost bought one for myself, but I wanted very fine precision at the lower end of the scale for use on non CO2 enriched planted tanks.

No luck there.........but I can measure CO2 enriched systems pretty well with these and take the portable unit around.

Regards,
Tom Barr

 

[dutchy]

It would be nice to have some data which I can use (graphs etc) There's a lot of resistance here against high CO2, mostly because of fish health. If I had some graphs which would show calculated and actual CO2 levels, that would help a lot.

Anyway it's strange. Almost no one thinks about O2 levels and fish health, they take it for granted and assume it's enough. But when it comes to CO2....

I don't want to give you a lot of work, but if it's possible it's a "nice to have".

regards,
dutchy

 

[Tom Barr]

I need to update my O2 meter also, that would be nice to have both plotted together.

That is the only true measure of fish health, you cannot discuss one with out the other, is it not 100% obvious?

Lungs, gills etc, they exchange the CO2 and take in O2.
So the ratio btw these is important, not so much their absolute values.

It's a flux question/issue, a rate of diffusion.


Regards,
Tom Barr

 

[yme]

There's a lot of resistance here against high CO2

what is high???
personally, a max of 30 ppm is simply not high.
various tanks that I measured contained 40-60 ppm CO2. the shrimps in those tanks were alive and kicking!

so, wat is the max?? my best guess is that 100-150 ppm is te maximum tolerable CO2 level. of course, this all depends on current, O2, fish load etc.

greets,

yme

ps: statements above hold only true if the oxyguard co2 meter is accurate at the measured values. (did not test it, manual states a 0-50 ppm range)

 

[dutchy]

Of course I should have specified. Let's say 40 ppm, which Tom uses frequently and also Tropica mentions as maximum?

Try to make these statements on a forum like AF. You better be ready for a 10 to 1 discussion.

regards,
dutchy.

 

[yme]

Try to make these statements on a forum like AF.

hihi.... as you know, I am not a member of AF, but I doubt anyone there has a co2 meter. Then it would be kind of a difficult discussion, wouldn't you say


but to come back to the O2/CO2 relation...... if the ratio is the most important thing: is my previous suggestion to control oxygen levels in the tank by an O2 electrode/solenoid valve/O2 tank very stupid??

greets,

yme

 

[dutchy]

I think an aerator pump and stone and a sensor that can make the power switch on/off would be enough. I kind of doubt if you really need it with good surface agitation, but that's just an assumption.

regards,
dutchy

 

[yme]

I kind of doubt if you really need it with good surface agitation, but that's just an assumption.

complete lack of knowledge from my side for sure!

I think an aerator pump and stone and a sensor that can make the power switch on/off would be enough.

just an airpump 24/7 is cheaper but can you increase the O2 level with a simple airstone beyond 8-9 mg/l? wouldn't you at least need some kind of reactor?

another point: would it be a good idea to lower the temperature of the tank 1 degree celcius? the colder the water, the more O2 it can contain. would a simple 1 degree drop contribute significantly to the ability of animals to cope with a higher CO2 levels?

and another thought: could you increase O2 levels by using ozone?? as we know, philips produces the "tropical aquarium purifier" an ozone apparatus for aquaria. although tom said that it doesn't do much/anything, I am wondering if you could increase the o2 level this way.
greets,

yme

 

[Tom Barr]

Cooler temps will increase the O2, and lower/slow the rates of plant growth.
So this is a good tool if your fish can handle it.

I have cardinals and my client's often keep discus.

Discus seem to be the most sensitive animals to CO2 IME.
We dialed the CO2 to 40-45ppm with good 7-8ppm of O2 to be their healthy frisky limit.

More than 45 ppm, they change the breathing rates and behavior.
Will they do fine at a higher CO2? Perhaps. Some plecos also seem more sensitive.

The main issue here is even if I get good readings etc..........few will ever have such a meter.
So the data will not be that applied.........rather..............it will be more something we can model and compare against, predict a general relationship, the larger picture.

Regards,
Tom Barr

 

[dutchy]

Discus seem to be the most sensitive animals to CO2 IME.
More than 45 ppm, they change the breathing rates and behavior.

kind of off topic, but can you tell me a liitle bit more? What was the behaviour change?

regards,
dutchy

 

[yme]

Cooler temps will increase the O2, and lower/slow the rates of plant growth.
So this is a good tool if your fish can handle it.

seems like a simple idea, right?
do you have any idea whether a drop from 24 to 23 degrees celcius would make a significant difference in the capability of fish to cope with high co2?
and do you know how much slower plants will grow when you lower the temperature 1 degree celcius? would it help in reality to limit growth (if you just lower the temp 1 or 2 degrees)
if it is significant, then it would be a good advice to lower the temp if you have stunting plants (due to low co2). lowering the temp would than be good for 2 reasons: 1: you can have higher co2 levels and 2: plant metabolism is slower.

probably this is just TOO easy, right?

in any case: I am looking forward to the results!!!

greets,

yme

 

[Biollante]

Not, Ifear, As Great As We Might Hope

seems like a simple idea, right?
do you have any idea whether a drop from 24 to 23 degrees celcius would make a significant difference in the capability of fish to cope with high co2?
and do you know how much slower plants will grow when you lower the temperature 1 degree celcius? would it help in reality to limit growth (if you just lower the temp 1 or 2 degrees)
if it is significant, then it would be a good advice to lower the temp if you have stunting plants (due to low co2). lowering the temp would than be good for 2 reasons: 1: you can have higher co2 levels and 2: plant metabolism is slower.

probably this is just TOO easy, right?

in any case: I am looking forward to the results!!!



greets,

yme

Hi,

Yes lowering the temperature help and in the range of aquarium temperatures, it is “relatively” dramatic, not sure, it is a great as we might hope.

Graphically http://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html, scroll down to CO2.

General Temperature and Pressure Effects on Solubility, http://www.elmhurst.edu/~chm/vchembook/174temppres.html.

This is a pretty-good explanation of the temperature pressure relationship for CO2 solubility http://www.google.com/url?sa=t&sour..._r4wvZ0Gw&sig2=1EaGHWHXcrC-I06ozNu11A&cad=rja .
MS Word Viewer http://www.microsoft.com/downloads/...88-7cfa-457a-9aec-f4f827f20cac&displaylang=en.

I will look at what I have and see if posting it would help.

Biollante

 

[Tom Barr]

You also slow down fish MET rates however, and plant demands=> less demand for O2 and CO2.......

Going from say 20C to 30C, you almost double MET rates as a general Q10 rule.

That is much more the larger looming issue vs the small amount of O2 between those two temps, if it was say 30C and 5C.........then it can be a fair amount.

that be some cold water.........

Regards,
Tom Barr

 

[rogerjackkson]

I've been thinking for some time. So, I already have some plans to play with them. I almost bought one for myself, but I think a very good accuracy in the scale of the use of low enriched cultivation of non-carbon dioxide tanks.