FastAquatics
Free aquarium tool · updated May 2026

Planted Tank CO2 Bubble Counter Calculator

Free CO2 BPS (bubbles per second) calculator for planted tanks. Enter tank volume + target ppm + plant load, get the bubble count target. Achieve green drop checker = ~30 ppm.

Reviewed by Fast Aquatics husbandry team·Updated May 2026

Target BPS + drop checker monitoring

How to use this calculator

CO2 dosing for planted tanks targets a drop checker reading of ~30 ppm (green color). The bubble counter sets the rate, but actual achieved CO2 depends on diffuser efficiency, photoperiod, and surface agitation.

Start low + ramp upBegin at 1 BPS for a 20-30 gallon tank. Monitor drop checker and fish behavior daily. Increase by 0.5 BPS every 3-4 days until target green color is reached.
Watch fishIf fish gasp at the surface or hover near surface, lower CO2 immediately + increase aeration. CO2 toxicity is fatal at 50+ ppm.
Solenoid timingRun CO2 1-2 hours before lights on. Off 1 hour before lights off. CO2 is wasted while lights are off.

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