Airstones in a planted tank?
- Thread starter gcis
- Start date
I'm Thinking the less suface agitation the better...for a planted tank. Someone with more experiance will help.
Both statements above are, of course, absolutely true! Turning the CO2 off at night invites pH swings = bad. Leaving CO2 on also invites asphyxiation of fish with elevated CO2 levels and depressed O2 levels due to normal respiration of plants = bad.
IMO, this dilemma is the biggest obstacle to overcome for those who use CO2 (especially if using compressed gas).
Ultimately, you'll have to investigate and find what is the best/balanced solution for your tank. I discovered that leaving the pH on 24/7 (to avoid pH swings) but running a large airstone at night was a reasonable compromise. Although I do experience some offgasing during darkness, I guard against low levels of O2 that could kill all specimens.
By not running the stone during the day, I preserve CO2 levels for uptake by the plants during the cycle of respiration where that gas is actively utilized (i.e. during the daytime).
EDIT: One of the biggest misconceptions around on this topic.... levels of dissolved CO2 gas in water and levels of dissolved O2 gas in water are totally independent of one another! CO2 does not "drive out" O2 or vice versa. Both gases can exist in high concentration simultaneously. The key matter is that airstones cause turbulence of water that leads to offgasing of CO2... the fact that it increases levels of dissolved oxygen does not in itself have a negative effect on CO2 levels.
IMO, this dilemma is the biggest obstacle to overcome for those who use CO2 (especially if using compressed gas).
Ultimately, you'll have to investigate and find what is the best/balanced solution for your tank. I discovered that leaving the pH on 24/7 (to avoid pH swings) but running a large airstone at night was a reasonable compromise. Although I do experience some offgasing during darkness, I guard against low levels of O2 that could kill all specimens.
By not running the stone during the day, I preserve CO2 levels for uptake by the plants during the cycle of respiration where that gas is actively utilized (i.e. during the daytime).
EDIT: One of the biggest misconceptions around on this topic.... levels of dissolved CO2 gas in water and levels of dissolved O2 gas in water are totally independent of one another! CO2 does not "drive out" O2 or vice versa. Both gases can exist in high concentration simultaneously. The key matter is that airstones cause turbulence of water that leads to offgasing of CO2... the fact that it increases levels of dissolved oxygen does not in itself have a negative effect on CO2 levels.
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plenty of people turn their co2 off and night with no ill effects. many of the well known people in planted tanks also so the ph swing for the most part doesnt effect the fish. unless you have a ph monitor the ph will swing. at night it will drop as co2 builds up and during the day it will go up.
i dont use any air pumps on my tanks. most tanks have plenty of surface agitation and dont need it.
i dont use any air pumps on my tanks. most tanks have plenty of surface agitation and dont need it.
pH swings due to fluctuating CO2 leves do not harm fish. pH swings in and of themselves, indeed, do not harm fish.
Surface agitation moves CO2 towards equilibrium with the atmosphere more quickly. So in a CO2 injected tank you don't want them because you're maintaining CO2 well above equilibrium. In a heavily planted non-CO2 tank, especially with moderate to high lighting, the CO2 will probably be below equilibrium because the plants are using it up, so it will actually be a benefit, drawing atmospheric CO2 into the water.
Surface agitation moves CO2 towards equilibrium with the atmosphere more quickly. So in a CO2 injected tank you don't want them because you're maintaining CO2 well above equilibrium. In a heavily planted non-CO2 tank, especially with moderate to high lighting, the CO2 will probably be below equilibrium because the plants are using it up, so it will actually be a benefit, drawing atmospheric CO2 into the water.