Question

Commercial club soda is produced by pressurizing water with 10 atmo- spheres of CO2. Find the value of KH for CO2 on the net or in the library, and calculate how much CO2 is in a 12 fl. oz. glass of club soda. When the CO2 reverts to the gas phase (as it eventually will in your digestive system), figure out how much volume it occupies at physiological conditions (37o C and 1 atm). Then contemplate burping.

Answer 1

Important notes on CO2 levels
The optimal safe C02 level for plant growth is 15-35 mg/l.
CO2 levels above 35 mg/liter are dangerous to fish.
This method is not accurate in tanks using peat or mature aquariums with a lot of organic matter and debris.

PH is a result of carbonate hardness (KH) and CO2 concentration, meaning that we can calculate the amount of CO2 in a body of water by measuring KH and PH. For most of our tanks KH is stable while PH varies according to CO2 levels. As CO2 levels increase the PH goes down. By cross referencing your KH and PH values in the table below you can quickly find out the CO2 concentration in your tank.

pH	6.0	6.2	6.4	6.6	6.8	7.0	7.2	7.4	7.6	7.8	8.0
KHº
0.5	15	9.3	5.9	3.7	2.4	1.5	0.9	0.6	0.4	0.2	0.1
1.0	30	18.6	11.8	7.4	4.7	3	1.9	1.2	0.7	0.47	0.3
1.5	44	28	17.6	11.1	7	4.4	2.8	1.8	1.1	0.7	0.4
2.0	59	37	24	14.8	9.4	5.9	3.7	2.4	1.5	0.9	0.6
2.5	73	46	30	18.5	11.8	7.3	4.6	3	1.9	1.2	0.7
3.0	87	56	35	22	14	8.7	5.6	3.5	2.2	1.4	0.9
3.5	103	65	41	26	16.4	10.3	6.5	4.1	2.6	1.6	1
4.0	118	75	47	30	18.7	11.8	7.5	4.7	3	1.9	1.2
5.0	147	93	59	37	23	14.7	9.3	5.9	3.7	2.3	1.5
6.0	177	112	71	45	28	17.7	11.2	7.1	4.5	2.8	1.8
8.0	240	149	94	59	37	24	14.9	9.4	5.9	3.7	2.3
10	300	186	118	74	47	30	18.6	11.8	7.4	4.7	3
15	440	280	176	111	70	44	28	17.6	11.1	7	4.4
20	590	370	240	148	94	59	37	24	14.8	9.4	5.9

The ideal CO2 concentration for a CO2 enriched tank is anywhere between 15ppm and 30ppm (ppm = mg/lt).

All you will need is an electronic scale that can be tarred. What this kind of scale does is it measures an item and sets the weight as 0. The subsequent readings show how much mass has been gained or lost in comparison to the original weight. Also, get a few bottles of soda, preferably the 16 ounce (454 milliliters) Pepsi bottles. Now you are ready to begin your experiment.

Place an unopened bottle on the scale and tare it. Now shake the bottle vigorously without opening it. You will feel a lot of reactions happening inside. Once the froth has subsided, open the bottle slowly and let the gas or the fizz escape. Make sure that you do not spill out any of the beverage at this point. Now measure the bottle again. Repeat the process a few more times. You will find that after 5-6 readings, the mass does not change much. This means, all the fizz has escaped. The difference, you see now, is the total amount of carbon dioxide present. To confirm your observations, try it with a few more bottles.

Approximately, this amount counts up to 2.2 grams/16 ounce. To get things in perspective, this is the amount of carbon dioxide that can fill up a liter bottle at normal pressure and temperature. But you must also note that some amount of carbon dioxide has dissolved in the liquid. This will not escape into the air unless the bottle is left open for a long time.