Yes, it’s true, air does contain a little bit of oxygen in the mixture of gases, but air is 4/5ths nitrogen gas contrary to popular belief. Nitrogen is inert, a filler gas.
Hmmm, apply Henry’s Law and start thinking out of the box hey. Good idea, applied chemistry.
Chillers are used to chill water, chilled water holds slightly more DO at colder water temps than warmer water with no roots, microbes or aerobes in that water consuming oxygen says the DO chart. The DO chart is based on air, air is a mixture of gases 79% nitrogen and 20.9% O2 and change, the partial pressure of O2 in air is 159 mm/hg at sea level, no more no less regardless of how much air goes through a bubbler, regardless of the bubble size a bubbler or diffused makes. I believe that’s still correct.
OK, now I’m thinking out of the box a bit as you suggested… what do think would happen if the water temp is constant 80% F and the partial pressure of O2 in air is increased from 159 mm/hg up to 275 mm/hg and that gas bubbled into the res water constantly, of course using Henry’s Law but modifying O2 gas partial pressure, not water temp achieving the goal of DO Saturation.
Henry’s law is cool, fun to play around with to achieve dissolved gas goals in different ways, manipulate water temps, salinity, gas tensions, barometric pressure... to achieve optimal DO saturations at warmer water temperatures. And never have to listen to a chiller running again albeit water chillers and the electricity to run them is really quiet cheap and not very costly at all.
Just thinking out of the box playing with Henry's Law.
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