Porting/Migrating Tanks from on CO2 method to another...


Prolific Poster
Dec 27, 2006

I wanted to see if anyone has experience migrating a tank from one CO2 strategy to another. In general, I think the changing of strategies would cause the plants to drop leaves and re-grow in most situations as they become highly adapted to their specific situation. In all cases, it is assumed one strategy is dropped for the other (no hybrid approaches).
Here are my hypothesis on what would happen for various migrations...

Non-Carbon (no excel, no CO2) -> CO2 - I think this will cause issues as the plants will take longer to adapt to an abundance of CO2. Algae is likely. This would be why Non-Carbon tanks should not have their water changed often.

Non-Carbon -> Excel - I believe this would not be an issue as the plants would be able to use the excel as a carbon source and the algae would not. The plants would not have to change strategy as the leaves (tissue?) are not absorbing CO2 only the excel through the water.

CO2 -> Non-Carbon - I don't this would go well. Likely the plants would die off causing a spike in Ammonia, and hence algae. If the CO2 was very slowly dropped off over the course of months (weeks?) the plants may be able to adapt, but I would expect leaf lose as the plants grow more adapted leaves to the situation.

CO2 -> Excel - I believe this would be similar to above. The plants would need to change their strategy to absord the carbon as it is in an entirely different form now. The plants would still have the advantage of available carbon, but their specialized leaves (tissue?) for high levels of CO2 absoprtion would no longer be adapted to the situation.

Excel -> CO2 - The plants leaves would be more specialized to absorb CO2... perhaps too specialized? Would they have too many resources devoted towards a resource that is now abundantly available? Maybe they would need to change strategies here as well.

Excel -> Non-Carbon - Would this be an acceptable migration? Could the plants adapt to no Carbon once the excel is removed?

Tom mentioned an enzyme that plants produce to acquire more CO2 from the atmosphere. I am assuming above that this enzyme is not necessary when using excel hence the differences in migration when using excel.


Guru Class Expert
Jul 9, 2007
Austin, TX
Very interesting thoughts. I'm interested to see what others think. I would have the same assumptions/questions as you have written above.

-Mike B-


Lifetime Charter Member
Lifetime Member
Mar 21, 2005
None of the bad things you list will happen if during transition you lower the light during the transition. When I get out of town for a week or two I just shut off the lights and the CO2 and when I return I resume the CO2 with half lights for a few days without issue. Light and Carbon consumption are directly linked so as long as you don't overdrive the system with lights you'll be OK whichever direction you go.