as temperature 'Increases,' dissolved oxygen 'decreases' ???

[Bubble_B0y]

I was wondering, is there a big difference between 22degrees celcius
& 26degrees celcius in terms of dissolved oxygen??


also i heard that ammonia toxicity increases with temperature??
is this true??

 

[RogerMcAllen]

There is a difference, but I am not sure how big it really is in that range. Something like 10 degrees C would be much more extrememe.

Yes, ammonia does become more toxic with an increase in temperature. This is why goldies, prodigous ammonia producers, should be kept in cold water as opposed to tropical.

 

[Bubble_B0y]

here is some facts:
thanx to algone.com

The amount of oxygen that can be dissolved (saturated) in the water is dependent on the water temperature and salinity (salt in water) levels. Increasing temperatures and salinity will allow less oxygen to be saturated in the water.

The following table shows saturation levels at different temperatures.

Salinity is measured in ppt and the dissolved oxygen content in mg/l (ppm).

˚C (˚F) 0 5 10 15 20 25 30 35
18 (64.4) 9.45 9.17 8.90 8.64 8.38 8.14 7.90 7.66
20 (68.0) 9.08 8.81 8.56 8.31 8.06 7.83 7.60 7.38
22 (71.6) 8.73 8.48 8.23 8.00 7.77 7.54 7.33 7.12
24 (75.2) 8.40 8.16 7.93 7.71 7.49 7.28 7.07 6.87
26 (78.8) 8.09 7.87 7.65 7.44 7.23 7.03 6.83 6.64
28 (82.4) 7.81 7.59 7.38 7.18 6.98 6.79 6.61 6.42
30 (86.0) 7.54 7.33 7.14 6.94 6.75 6.57 6.39 6.22

Please note that a salinity of 0 corresponds to a freshwater tank.

For example, a freshwater aquarium with a temperature of 75 ˚F can dissolve 8.4 ppm of oxygen. A saltwater tank with a temperature of 82.4 ˚F and a salinity of 15 ppt can dissolve 7.18 of oxygen.

The above levels show 100% saturation, the maximum possible. The average saturation in an aquarium is about 70%

The level of dissolved oxygen varies throughout the day, it is higher during the lighting period and has the lowest concentration in the early morning hours.

A dissolved oxygen content of 5-7 ppm is sufficient, first signs of stress will show if the content drops below 4 ppm, fatalities can be expected at 2 ppm.

 

[Bubble_B0y]

more facts about ammonia:

Ammonia is MORE toxic at a higher pH and a higher temperature.
Ammonia toxicity is significantly influenced by temperature and pH. The lower the temperature and pH the more ammonia can be tolerated.
Lethal ammonia concentrations at a pH of 6.5 are 0.73 ppm, while at pH 8.5 only 0.17 ppm are considered lethal to inhabitants.

A fish tank kept at 68 degrees F can tolerate more then twice the amount of ammonia as a tank kept at 86 degrees F.