# pH/KH/CO2 and Amazonia2



## beantown (Oct 22, 2007)

I posted this over in the fertilzing section, but no hits, so I'll try you guys and gals over here! 

As Amazonia I and II buffers the water, does the whole pH/KH/CO2 relationship become null and I will no longer be able to tell ppm CO2 from water tests. Why or why not?

Thanks for any help!


----------



## hinoone66 (Jan 3, 2009)

Most likely will alter readings. Due to the fact your altering ph, and kh. Try testing co2 with drop check, seems to give more accurate co2 reading for me.


----------



## ray-the-pilot (May 14, 2008)

beantown said:


> I posted this over in the fertilzing section, but no hits, so I'll try you guys and gals over here!
> 
> As Amazonia I and II buffers the water, does the whole pH/KH/CO2 relationship become null and I will no longer be able to tell ppm CO2 from water tests. Why or why not?
> 
> Thanks for any help!


My feeling is, no, it will not be a problem with the pH/KH/CO2 relationship but it is hard to say for sure.

I'd suggest that you write to the makers of the substrate and ask them. Then do what they say.


----------



## Quetzalcoatl (Feb 13, 2009)

The relationship between pH, KH and CO2 does not change based on what soil you use.
You can find the exact equation online, but the general idea is that KH act as buffer for pH, which means if KH is higher, you will need to add more CO2 to drop pH where as if KH is lower, little bit of CO2 will alter pH.

Amazonia will lower pH and KH for sure. It also seem to lower GH but from my experience not that much. Note that even though Amazonia alter your water's pH and KH, it does not alter the overall relationship between pH, KH and CO2. The general rule still apply and the formula will continue to work.


----------



## ray-the-pilot (May 14, 2008)

Quetzalcoatl said:


> Amazonia will lower pH and KH for sure. It also seem to lower GH but from my experience not that much. Note that even though Amazonia alter your water's pH and KH, it does not alter the overall relationship between pH, KH and CO2. The general rule still apply and the formula will continue to work.


This is not exactly true but it is mostly true.

If the substrate adds an acid that has a pKa in the range of interest (5.0 - 8.0) it may cause a deviation in the general rule. The only typical acid in that range is phosphoric acid but there are any number of acids used to buffer the pH in water that is why you should check with the supplier about the effect.


----------

