CO2 Chart Calculator

Determine CO2 concentration using pH and KH Relationship.

pH Value

KH (dKH) - Carbonate Hardness

CO2 Concentration12.0 ppmlow

Note: Optimal range for planted tanks is usually 15-30 ppm. Too low limits growth. Too high endangers livestock.

Reference Table (pH vs KH)

pH \ KH	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
6.0	30	60	90	120	150	180	210	240	270	300	330	360	390	420	450
6.2	19	38	57	76	95	114	133	151	170	189	208	227	246	265	284
6.4	12	24	36	48	60	72	84	96	107	119	131	143	155	167	179
6.6	8	15	23	30	38	45	53	60	68	75	83	90	98	105	113
6.8	5	10	14	19	24	29	33	38	43	48	52	57	62	67	71
7.0	3	6	9	12	15	18	21	24	27	30	33	36	39	42	45
7.2	2	4	6	8	9	11	13	15	17	19	21	23	25	27	28
7.4	1	2	4	5	6	7	8	10	11	12	13	14	16	17	18
7.6	1	2	2	3	4	5	5	6	7	8	8	9	10	11	11
7.8	0	1	1	2	2	3	3	4	4	5	5	6	6	7	7
8.0	0	1	1	1	2	2	2	2	3	3	3	4	4	4	5