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Re: Temperature effect on dissolved gas

     >I was reading the latest Aquatic Gardeners Association's Jounal and I 
     >came across this article about substrate of Planted tank. It was 
     >stated that gas (oxygen and CO2) will not dissolved  properly  if the 
     >water temperature of water is too warm. I presume that that will mean 
     >the PH will be high and alot of CO2 will be wasted into the 
     >atmosphere and algea will grow. Does anybody have any idea of this???
     I am not a subscriber to TAG, so I have not read that article.
     Oxygen saturation at different temperatures in fresh water is given in the 
     following table:
     Temperature          ppm Oxygen (O2) @ 
     ------------       --------------------- 
     C       F          sea level   2,000 ft 
     10      50           11.3         10.5 
     15      59           10.1          9.4 
     20      68            9.1          8.4 
     25      77            8.2          7.6 
     30      86            7.5          7.0 
     35      95            6.9          6.4
     At typical aquarium temperatures (20-30 C), there is ample oxygen at 
     saturation.  However, if you have poor water circulation and/or a high 
     oxygen demand, dissolved oxygen could be well below saturation, but this 
     could occur in a cool (20 C) or a warm (30 C) aquarium.  A tight-fitting 
     cover on a CO2-injected aquarium could also lead to low oxygen.
     The solubility of carbon dioxide is complicated because of its' reaction 
     with water, but I would have to say your water chemistry, surface 
     agitation, and plant biomass has a far greater influence on the amount of 
     dissolved CO2 in your aquarium than temperature. An excellent discussion 
     can be found at http://www.cco.caltech.edu/~aquaria/Krib/Plants/CO2/
     Kind regards,