CO2 Injection Calculator

CO2 rate for planted aquarium from tank size and plant mass.

Tank Volume (gallons)

Target CO2 (ppm)

Carbonate Hardness (dKH)

Target pH

Tab to move between fields

CO2 at Target pH (ppm)

Bubble Rate (bubbles/sec)

1.4

pH for Target CO26.68

CO2 Flow (mL/min)4.17

Expected pH Drop0.92

Daily CO2 Usage (grams)4

Tank Liters75.71

How to Use This Calculator

How the result changes with Target pH

Tank Volume (gallons): Total water volume of your planted aquarium in US gallons.
Target CO2 (ppm): Desired CO2 concentration. 20-30 ppm is ideal for most planted tanks. Above 30 ppm can stress fish.
Carbonate Hardness (dKH): Your water's KH reading in degrees of carbonate hardness. Typically 3-8 dKH.
Target pH: Desired pH level. CO2 injection lowers pH. Most planted tanks target 6.4-7.0.

CO2 at Target pH (ppm): CO2 concentration that results from your KH at the target pH (3 × KH × 10^(7-pH)).
pH for Target CO2: The pH your water will settle at when target CO2 concentration is reached.
Bubble Rate (bubbles/sec): Estimated bubble counter rate to achieve target CO2.
CO2 Flow (mL/min): Approximate CO2 gas flow rate.
Expected pH Drop: pH reduction from atmospheric equilibrium (~3-4 ppm CO2) to your target.
Daily CO2 Usage (grams): Estimated daily CO2 consumption assuming 8-hour injection during photoperiod.

Identify Input Parameters
4 parameters
Tank Volume (gallons) = 20, Target CO2 (ppm) = 25, Carbonate Hardness (dKH) = 4, Target pH = 6.8 = 4 input(s) provided
Calculate CO2 at Target pH
CO2 at Target pH = 3 * kh * pow(10, 7 - phTarget)
19 = 19
Calculate Bubble Rate
Bubble Rate = (tankVolume / 12) * (targetCo2 / 30)
1.4 = 1.4
Calculate pH for Target CO2
6.68 = 6.68
Calculate CO2 Flow
CO2 Flow = bubbleRateBps * 60 * 0.05
4.17 = 4.17