Air pumps off in the day?

[PlantedAquaria]

Daylight hours: plants require co2 more than oxygen as they photosynthesise

Night time hours: plants require oxygen as they respire.

Given that an air pump, as far as I can see, oxygenates the water, is it best to have air pumps off in the day to allow more co2 to accumulate for photosynthesis and on all night to infuse oxygen for respiration?

Assuming a canister filter is also present.

 

[Aiken Drum]

Yes, that is correct.

Also, turn off CO2 at night

 

[Mr. Overfilter]

Yes, that is correct.

If a planted tank depends on surface agitation\flow for oxygenation will that create a problem?

 

[Aiken Drum]

If a planted tank depends on surface agitation\flow for oxygenation will that create a problem?

Its about balance. In a high light situation with CO2, the plants will produce O2 through photosynthesis at a higher rate than it is depleted through other processes.

With the CO2 on and airstone off during the day, you should have high CO2 and O2 dissolved in the water. You turn off the CO2 and turn on the airstone at night so you arent wasting CO2 and maintain O2 through surface agitation. CO2 and O2 arent interchangeable. Its possible to have high enough levels of both with the correct balance of CO2 and light and plants.

 

[Mr. Overfilter]

Its about balance. In a high light situation with CO2, the plants will produce O2 through photosynthesis at a higher rate than it is depleted through other processes.

With the CO2 on and airstone off during the day, you should have high CO2 and O2 dissolved in the water. You turn off the CO2 and turn on the airstone at night so you arent wasting CO2 and maintain O2 through surface agitation. CO2 and O2 arent interchangeable. Its possible to have high enough levels of both with the correct balance of CO2 and light and plants.

The more I learn about planted tanks the more complex they seem. Is there a device (controller) that can achieve/maintain this balance electronically or is it all about fingers?

Great information as usual, Aiken. Thanks!

 

[Caliban07]

The more I learn about planted tanks the more complex they seem. Is there a device (controller) that can achieve/maintain this balance electronically or is it all about fingers?



Great information as usual, Aiken. Thanks!

Co2 regulators usually come with a solenoid so that once you have set the desired co2 input you can leave the needle valve open and have the solenoid close off the co2 when the power is interrupted by a timer and vice versa.

Someone fancy like Delapool will also use a pH probe so that the co2 switches off when the desired pH drop is achieved.

The air pumps that drive the air stones you just have on a timer to come on at night. I’m not a co2 user currently so I leave my airstone on 24/7.