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Old 29-03-2003, 05:08 PM
Richard
 
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Default How long does 5lb CO2 Tank Last/ pH Controller source


"Henry" wrote in message
...

I am getting pretty large pH swings. Part of the problem, I think, is that
the tank is in a room that gets quite cold at night. My bubble rate

actually
increases at night (Temp drops, C02 tank pressure drops but the secondary
pressure out to the tank increases from 20 to 23 or 24 pounds .... is this
normal with a relatively large temperature swing .. about 15 degrees F...

in
a room?)

The aquarium itself is well heated, so temp fluctuations are not a problem
with it, only with the C02 tank/regulator. My bubble rate fluctuates from
about 90/min (at night) to about 45 during the day. The regulator assembly
is new within the last month.

I guess I could just get a solenoid and hook it up to the timer for my
lights to shut the C02 off at night, but I am also getting some pretty

wide
pH swings during the day (but not as bad as at night).

My pH is swinging between about 6.8 - 7.4

What do people consider to be acceptable Ph swings?

My KH hardness is about 3.5 degrees. I am inclined not to mess with my

water
chemistry if possible.



Check out:

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
http://www.thekrib.com/Plants/CO2/

See if these help.

Based upon your kH with no phosphate buffers present, your pH swing
indicates you are going from very little CO2 (4ppm), to about 16ppm. With
DIY CO2 i never had a problem, but our setup was some different than the
majority, and we only had a pH swing of .3 on average.

In my opinion, your target CO2 concentration should be based upon how many
WPG (watts per gallon) of light you have.

The temp swing in our house is 15-20 degrees depending upon how cold it is.
Keep a sharp eye on your kH, as adding CO2 will lower it as time goes by.

In my opinion, save the money for now, and work on stablizing things some,
then if you still feel you would like to try it out, go for it.