Co2

[fatheadminnow]

I have a 29 gallon, soon to be planted, and I am going to be injecting CO2.

I am going to be making a home-made unit using a paintball CO2 tank. The tank is a 20 ounce tank, and I was wondering how long this will last if the CO2 level in the tank is kept around 25-30ppm.

Also, how do you measure CO2 levels in the tank, and do you turn the CO2 off at night?

Thanks
-FHM

 

[IovaykInD]

It will depend on how well you diffuse your co2, but 20 ounces will not last you too long.. generally people go for 2.5 or 5lb cylinders and those last around a few months to almost a year. I'd say it would last you about a month or two, again, it depends how well you diffuse it if you want to keep it 25-30ppm

 

[Renate]

Co2 is measured best with drop checker. You can make 1. I have read that you

Surface agitation allows CO2 to escape into the air. You can hold in more CO2 by reducing surface agitation, but be cautious, since surface agitation is also the source of O2 for your fish. With too little surface movement, you may cause your fish to suffocate.
Gpodio APC

An example of good surface agitation can be seen at hoppy's thread
He turns his off at night.

Just click on the words underlined for the links.

If your water has a high ph and is soft there are buffers in it. Here is a calculation I came across:
Hanns-J Krause CO2 Test
Author Handbook Aquaria Technology
Krause recommends a different method to measure CO2 content. That method is insensitive to the presence of unusual buffers.

Step 1:
water sample
air from an air pump into the sample for a few minutes.
sets the CO2 level at 0.6ppm (=X).

Step 2:
water sample
blow through the straw into the water sample for a few minutes sets the CO2 level at 60ppm.(=Y)

Step 3:
CO2 of 10-20ppm is at the pH # 2/3 of X - Y:
pH,opt = X +.67*(Y-X).

As an example, if you measure pH 8 with the first sample, and pH 6.5 with the second sample, a tank pH of 7 corresponds to 30ppm CO2, regardless of any buffers that might otherwise confuse a CO2 test or distort the charted values.

PH Opti (6.995) = x(6)*(y(8)-X(6)

 

[fatheadminnow]

Thanks for both of your replies!

-FHM

 

[aaronnorth]

use a drop checker (see my signature for a detailed guide). A smal ripple will be ok for surface agitation - plants input O2 into the water aswell