Working Out Co2 Bubbles Per Second

[sophos9]

Hi

I have a 180litre tank with pressurised CO2. Using the 24hr PH test a 1PH drop should be equal to 30ppm

How do you work out CO2 content using KH, I'm led to believe its the volume of the tank in litres multiplied by the kH divided by 50 will give you the approximate number of bubbles per minute.

So in my case (180*3)/50 = 10.8 BPS

Is this right or am I ODing my fish?

 

[smithrc]

Something very similar worked for me...


http/www.fishforums.net/index.php?s=&amp...st&p=645016

That will only give you a bubbles per minuite figure to work around...


Now... are you sitting comfy?

All sounds very logical.

If you're mathematically inclined here's an explanation for it.

A simple formula for relating CO2 to pH and KH is:

CO2 = 3xKHx10^(7-pH)
where CO2 in ppm and kH in degrees.

Taking logs of both sides and after a bit of algebra you get:

pH = 7-log(CO2/3KH)

If you now consider a pH swing pH(2) - pH(1) and assume KH is constant then after a bit more algebra you find KH drops out and you're left with

pH Swing = pH(2)-pH(1) = -log(CO2(2)/CO2(1))

So if your CO2 starts at 3ppm and increases to 30ppm then the pH swing is equal to -log(30/3) = -1.

Ie pH reduces by 1 regardless of kH.

Hope this isn't too confusing.

 

[sophos9]

Ahhh.... I got the calculation with my pressurised D&D kit, so it worked out well for you then?