Is there enough oxygen?

[thebiggerthebetter]

My understanding the equilibrium point is 16 ppm or mg/L with nothing in the water consuming the oxygen and nothing generating it. With plants it is possible to get a number exceeding 16 but usually in a fish tank an oxygen sensor (~$200) would read less than 16. I think 7 ppm is roughly borderline for an average fish's comfort but DO requirements of fish vary.

 

[squint]

My understanding the equilibrium point is 16 ppm or mg/L with nothing in the water consuming the oxygen and nothing generating it. With plants it is possible to get a number exceeding 16 but usually in a fish tank an oxygen sensor (~$200) would read less than 16. I think 7 ppm is roughly borderline for an average fish's comfort but DO requirements of fish vary.

Saturation is affected by elevation, barometric pressure, salinity, and temperature but mostly temperature.

I like to see over 6 mg/L in tropical tanks but heavily stocked tanks with dirty filters can make that challenging.

 

[thebiggerthebetter]

Saturation is affected by elevation, barometric pressure, salinity, and temperature but mostly temperature.

I like to see over 6 mg/L in tropical tanks but heavily stocked tanks with dirty filters can make that challenging.

Thank you much for this and for correcting my wrong recollection.

So at average conditions, the saturation point is much lower, around 9 ppm.

 

[RD.]

Yep, this can be a very fine line in a heavily stocked tank. I have seen tanks wiped out when a power outage hit in the night, and the owner didn’t notice until 8-10 hours later.