Co2 Fluctuation

[r.w.girard]

I was reading recently in a pinned article, that CO2 fluctuation is the last thing that one wants in a planted tank and that you either need constant CO2 injection or you need to, essentially, get rid of all of the CO2 in your tank and keep it at a zero. Thus it was being recommended that, in a low tech tank, you get your CO2 low by letting a sit a few days before a water change [to remove the CO2 from the tap water] and then to reduce water changes to once a month. However, that was meant to work in a densely planted tank that could deal more easily with the waste production of the fish in the tank. My tank being small [10 gallons] and not heavily planted [shall we just call it well planted: there is roughly one plant per 2 gallons], I do not trust the idea of not doing water changes regularly. This got me thinking, CO2 fluctuation is caused by the constant leaching of CO2 [ie. plants and surface]. If we want to keep the CO2 at a more constant level, wouldn't more water changes do the same thing? One ever 3/4 days instead of every 7? Wouldn't that give us increased growth [due to a higher concentration of CO2 in the water at all times] and less algae [less fluctuation]?

I ask because of the appearance of black beard algae in my tank, along with green spot algae, both of whose arrival coincides with that of summer.

Tank specs: 10 gallon, Marina S15 filter. 15w fluorescent lighting.

 

[aaronnorth]

This got me thinking, CO2 fluctuation is caused by the constant leaching of CO2 [ie. plants and surface]

There is an equilibrium point, where the production of CO2 from organisms and CO2 absortion at the surface levels out with the intake of CO2 by organisms and gassing off of CO2 at the surface

If we want to keep the CO2 at a more constant level, wouldn't more water changes do the same thing? One ever 3/4 days instead of every 7? Wouldn't that give us increased growth [due to a higher concentration of CO2 in the water at all times] and less algae [less fluctuation]?

The equilibrium point will be reached for CO2 after a few hours so it really isnt necessary to let the water sit.
Doing one water change a month gives you one fluctuation a month. If you do it every few days then you will get a fluctuation every few days.

Thanks, Aaron