Aeration in aquariums is essential for maintaining high dissolved oxygen levels, crucial for fish respiration and for other inhabitants including beneficial aerobic bacteria. It's also necessary for facilitating gas exchange to remove excess carbon dioxide (after the photo period that plants require for photosynthesis) and to allow easy plant oxygen respiration at night. Aeration increases surface agitation, stabilizing pH, aiding in waste decomposition, and ensuring a healthy, stable aquatic environment, particularly at night.
Aquariums need aeration because the entire ecosystem needs oxygen
- 3 essential functions aeration provides
- Aeration helps balance the amount of CO2 in the water column
- CO2 is injected during the photo period, but CO2 levels would remain high even after injection shuts off for the night
- During the day plants are experiencing photosynthesis, consuming CO2 in the water and releasing oxygen
- During the night, photosynthesis declines and plants switch to respiration consuming oxygen and releasing CO2
- If there's too much CO2 in the water at night, the plants won't have enough oxygen for respiration
- Aeration helps release some of the CO2 from the water column at night to maintain a healthy level after the light is out and photosynthesis has ceased, and plant respiration begins
- Aeration breaks up the collection of oil film on the water surface (surface biofilm) via agitation
- Injection of CO2 during the photo period tends to contribute toward surface biofilm
- Surface biofilm hinders gas exchange between air and water
- Breaking up that film promotes gas exchange, allowing healthy balance of gases dissolved in the water column
- Aeration vitalizes the growth and maintenance of beneficial aerobic bacteria colonies in the ecosystem
- Essential bacteria and other microorganisms need oxygen to live and function, purifying the water, and driving the denitrification process that controls ammonia, nitrite, and nitrate in the water column
- When the CO2 to oxygen ratio is out of balance with oxygen deficiency, the beneficial bacteria suffer
- To keep these aerobic bacteria functioning well, it's important to pump oxygen into the water, especially at night
Running aeration (air pump and air stone) while injecting CO2 tends to cancel each other out
- Carbon dioxide (CO2) should be injected during the day, and aeration (oxygen) should be run at night
- CO2 injection should timed to begin at least 1 hour before the beginning of the photo period, and timed to stop about 1 hour before the photo period ends
- Aeration should be timed to begin a couple hours after the photo period ends and timed to stop about 1 hour before the photo period begins
- Run CO2 injection during the day, and run aeration (oxygen) during the night, with the timing offset by a couple hours at both ends of the on/off cycles to prevent excessive pH swings
- When CO2 is injected into the water column the pH level decreases (producing carbonic acid)
- When aeration pumps oxygen into the water column, the pH level increases
- Allowing time between injecting CO2 and running aeration, gives the CO2 and oxygen levels a chance to increase and decrease more gradually, easing the pH transition