Pumping atmospheric air into the plant aquarium.

[Stan510]

What is the final word on that with non Co2 aquariums? I use an air pump that feeds into the vortex of a powerhead and that returns close to the out flow of the big mag drive pump of the inside filter so blasts those bubbles across the top of the 240 gallon.
I don't have scientific Co2 measuring devices,but does the pumping of so many millions of bubbles bring that atmosphere Co2 to the plants? The aquarium seems healthier with the aeration. I just can't prove it.

 

[StevenF]

Whenever water mixes with air the water any excess CO2 in the water will be released into the air. If the water is deficient in CO2 mixing air with water will increase CO2 levels in the water. Mixing air with water is always good becuse it helps keep CO2and oxygen levels stable in the water.

Also you don't have to use an air pump A water fall will work or simply creatings wa small waves or ripples in the water surface will help with gas exchange.

As to CO2 measuring devices there basically aren't any. IN the lab to measures CO2 levels in water involves filtering out organics, and KH and then measuring CO2. Organics and carbonates must be removed to get an accurate number. Liquid test kits are available but they only work with pure water. Som aquarium test strips will generate a CO2 number by that number is generated from KH and PH valve and a look up table. These are not accurate because they don't take into account water chemistry. Many people with CO2 aquarium use a drop checker to monitor their CO2 levels. But these only detect CO2 outgassing from the water. Which only happens when there is more CO2 in the water than their is in the air.

 

[Colin_T]

Normally aeration helps drive out excess carbon dioxide (CO2) and introduces oxygen (O2) into the water.

Water movement in a plant tank does help to circulate nutrients including CO2, and deliver these to the plants.

 

[WhistlingBadger]

Generally aeration decreases CO2.

 

[StevenF]

Generally aeration decreases CO2.

Note true. It depends the circumstances. If you have a container of pure the PH should be 7 because pure water has no acids or bases ion it. Add CO2 PH will drop. Remove it PH will go up.to 7. Add ammonia ( as base) the PH will increase and can hit 10 or more.

Pure water in a container well always register as slightly acidic due to water absorbing CO2 from the air. Now I did put a container of pure water checked the PH and then used an air pump to aerate the water. I was able to drive the PH down in the container. Based on this chart of CO2 concentration, and PH I likely got close to 400ppm. Now I don't have lab qualityPH sensor and I had to leave it in the water for a long time to get a stable reading. But It did show aertation pushing the PH down.

In high tech tanks with injected CO2 the drop checker used to monitor CO2 levels can only detect CO2 if there is more CO2 in the water than the air.So In high tech tanks aeration will cause CO2 to drop. So most believe aeration only drive out CO2.

 

[Oblio]

A pH of 7 (pure water) indicates H+ (Acid) and OH- (Base) ions are in equal proportion, not that they are absent..

Pure water is neutral. When an acid is dissolved in water, the pH will be less than 7 (25 °C). When a base, or alkali, is dissolved in water, the pH will be greater than 7. A solution of a strong acid, such as hydrochloric acid, at concentration 1 mol dm−3 has a pH of 0. A solution of a strong alkali, such as sodium hydroxide, at concentration 1 mol dm−3, has a pH of 14. Thus, measured pH values will lie mostly in the range 0 to 14, though negative pH values and values above 14 are entirely possible. Since pH is a logarithmic scale, a difference of one pH unit is equivalent to a tenfold difference in hydrogen ion concentration.

The pH of neutrality is not exactly 7 (25 °C), although this is a good approximation in most cases. Neutrality is defined as the condition where [H+] = [OH−] (or the activities are equal). Since self-ionization of water holds the product of these concentration [H+]/M×[OH−]/M = Kw, it can be seen that at neutrality [H+]/M = [OH−]/M = √Kw, or pH = pKw/2. pKw is approximately 14 but depends on ionic strength and temperature, and so the pH of neutrality does also. Pure water and a solution of NaCl in pure water are both neutral, since dissociation of water produces equal numbers of both ions. However the pH of the neutral NaCl solution will be slightly different from that of neutral pure water because the hydrogen and hydroxide ions' activity is dependent on ionic strength, so Kw varies with ionic strength.

If pure water is exposed to air it becomes mildly acidic. This is because water absorbs carbon dioxide from the air, which is then slowly converted into bicarbonate and hydrogen ions (essentially creating carbonic acid).

CO2+ H2O ⇌ HCO−3+ H+

pH - Wikipedia

en.wikipedia.org