Originally Posted by madyotto
but we do have to remember that in the night plants consume oxygen and there for leaving an accumulation in carbon dioxide for the plants to eat as the light returns in the morning
meaning that aeration is very good if used right and at a very slow rate
now brain storming here a bit but what if
we had a timer on our air pump's and having no air for two hours before light to magnify this carbon dioxide build up
this must be a very stable setup and also maybe even have it off for a few hours in the day too
We should perhaps clarify things. If we are considering natural planted tanks, meaning those with no CO2 diffusion at all, then there is no need for any aeration beyond what the filter will provide. Oxygen is not likely to be deficient in a natural planted tank unless there is some sort of a disaster.
If you are considering planted tanks having CO2 diffusion, then that is normally turned off with the lights (otherwise it is being wasted). Some do suggest aeration at night in these tanks, since the planting itself is often quite different so the normal balances are not the same.
The CO2 in a natural planted tank rebuilds during darkness, but this is never going to be catastrophic unless again you have some abnormality occur. Tests have suggested that the CO2 level that rebuilds is most likely to be exhausted by the plants after just a few hours of light (photosynthesis). This is the reason behind to so-called "siesta" approach to promote more plant growth without CO2 diffusion.
Another point is that Oxygen increases can be detrimental to plants. In high oxygen environments, plants have difficulty assimilating nutrients. A small dissolved oxygen content is required for plants. Higher dissolved oxygen cause nutrients such as iron to bind with the oxygen, becoming too large for plants to assimilate. High oxygen levels also inhibit other nutrient uptake.