Judging Co2 Amount using Ph & KH

Here is a helpful tool for figuring out how much Co2 is in your tank when growing plants. There's debate as to whether or not it's an accurate method or not, but I find it's a good way to get a general idea.

Fairly simple, just test your KH & Ph, and find where they cross on the chart. Ideally, between 10 & 30 is the sweet spot. Any more than 30, and the Co2 may harm your fish.

Co2: KH/pH Chart
	pH	6	6.2	6.4	6.6	6.8	7	7.2	7.4	7.6	7.8	8
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		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		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		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		118	75	47	30	18.7	11.8	7.5	4.7	3	1.9	1.2
5		147	93	59	37	23	14.7	9.3	5.9	3.7	2.3	1.5
6		177	112	71	45	28	17.7	11.2	7.1	4.5	2.8	1.8
8		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 problem with this method I think is that volume doesn't come into play.