But that does get me wondering, how does the oxygen get into the reef tank? Is it just produced as a bi-product of the live rock eating CO2 or what?
Oxygen enters the aquarium in a few ways. Surface agitation is a major factor. Every time the surface of the water is broken, gas exchange takes place. Co2
is normally vented off and O2
is able to enter the water. Another way Oxygen is able to "get in' is through plant life in the aquarium during photosynthesis, whether that be algae, plants, etc.
You could also "bubble" Oxygen in by using air pumps, but this is really un-needed in a properly setup fish tank. This is mostly used in FW
but even then that is for show.
Is this true? I could see how this idea could come to be(less O2 at altitude
Ok. This is a "pet peeve" of mine from my diving school days. There actually is not less oxygen at higher altitudes. The makeup of oxygen in the atmosphere is the same at 100 ft as it is at 50,000 ft (~21%). The difference is there is less air pressure holding the oxygen molecules together at higher altitudes, so in fact, they are spread out more at higher altitudes than at lower altitudes. If we could "suck" in more air at higher altitudes, we would be able to breath in those low pressure scenarios.
Just thought you might like a quick science lesson.