Good CO2 levels

[cubsfan]

I just set up a new planted aquarium which is running with a yeast generated CO2 system. I have measured the pH at about 6.5, and the KH at about 4. I don't have a kit to directly measure CO2 levels, so I have just been going off of a CO2 calculation table that uses these two parameters to calculate the ppm of CO2 in the tank. According to the chart, the tank then has 40 ppm CO2, which the chart states is an unhealthy level for fish. Is this truly unhealthy for the fish? Also, are these calculation tables accurate, or is there some preferred method for measuring CO2 content.

Note: I currently have 3 black phantom tetras in the tank, along with a small group of panda cories. I plan on adding a pair of apistogramma in the near future. Does this environment sound suitable?

Thanks in advance for any advice on this subject!

 

[aspen]

i believe it is unlikely that your tank has 40 ppm of co2 from a diy set-up. to get a more accurate measurement, take a sample of tank water and aerate it, then test it. there are a few things which can skew the tables, but this is the method that a lot of people use to measure their co2.

the reason i like to use a tank sample is, that you can directly see the rise in ph before and after aerating, and this will take some other factors out of the equation, as compared to simply measuring tap and comparing it to the tank. you aren't using any discus buffer, peat moss etc are you? just water and co2? otherwise things may not make sense when you are doing your calculations.

as for whether your set-up is suitable, well, it is great except for the cories, imo. some don't seem to have problems, but i've seen the little buggers move through and clean out a nest of eggs in a second.

rick

 

[LyreTail]

You can get 40 ppm out of a yeast system if the tank is small enough and has little surface agitation, but only for about the first week and then production tends to drop off.

Use less yeast in your mixture and it will last longer, produce a lower peak of CO2 production

The CO2 charts can be fairly inaccurate because the KH and pH numbers are not perfectly accurate as far as testing errors go. Another thing to consider is additional acid inputs into the system, including peat filtration, pH reducers or just natural nitrification or rotting plant matter

 

[cubsfan]

Thanks again for the advice!

Should I assume then that a DIY system is not going to produce harmful levels of CO2 in the water? I figured that the chart wasn't going to be accurate because the CO2 levels it indicates varies a huge amount even over 0.5 pH

 

[CKfish]

In a fishless experiment, I got a 10 gallon tank past 80 ppm CO2, so it is possible to reach lethal levels. It will vary depending on CO2 output and the amount of surface exchange occuring in your tank.

 

[farm41]

In a fishless experiment, I got a 10 gallon tank past 80 ppm CO2, so it is possible to reach lethal levels. It will vary depending on CO2 output and the amount of surface exchange occuring in your tank.

Precisely why any addition of co2 should be started slow and then add more as conditions warrant it.

Whether it be diy or pressurized. 8)