GoGuppy
23rd September 2008, 09:11 PM
Hi all
I thought I would share with all the attached graph, which I developed a few years ago from data widely available on the net at many locations. The graph may interest those who like planted fresh water tanks.
It shows the relationship between the main parameters governing you tank water CO2 level, namely carbonate hardness (measured in KH or parts per million, ppm) and pH level (ranges in most planted fresh water tanks between about 6.5 and 7.5, but there are also many planted tanks running uccessfully outside this range).
To use the graph you need to know, if not accurately at least roughly, two out of the above three parameters, typically that would be the KH and pH. Best way to find out what these are is to buy test kits for pH and KH, if you do not already have these.
Having established the pH and KH values for your tank water, lets assume that these are 6.8 and 5 degrees KH respectively, use the graph as follows:
On the lower horizontal axis find the value for 5 KH, draw an imaginary line vertically upward until you reach the sloping line for pH=6.8 . At this intersection move horizontally across to the left scale and read of the CO2 value, which in this case is about 23ppm.
I like to keep the CO2 up around the 25ppm mark in my tank and use a pressurised system with digital controller to achieve this. The graph also shows the typical ambient CO2 level, that is the level without injecting any external CO2 to the tank, which is typically around the 2.5 to 4ppm level.
Hope you find the above useful.:)
Cheers
I thought I would share with all the attached graph, which I developed a few years ago from data widely available on the net at many locations. The graph may interest those who like planted fresh water tanks.
It shows the relationship between the main parameters governing you tank water CO2 level, namely carbonate hardness (measured in KH or parts per million, ppm) and pH level (ranges in most planted fresh water tanks between about 6.5 and 7.5, but there are also many planted tanks running uccessfully outside this range).
To use the graph you need to know, if not accurately at least roughly, two out of the above three parameters, typically that would be the KH and pH. Best way to find out what these are is to buy test kits for pH and KH, if you do not already have these.
Having established the pH and KH values for your tank water, lets assume that these are 6.8 and 5 degrees KH respectively, use the graph as follows:
On the lower horizontal axis find the value for 5 KH, draw an imaginary line vertically upward until you reach the sloping line for pH=6.8 . At this intersection move horizontally across to the left scale and read of the CO2 value, which in this case is about 23ppm.
I like to keep the CO2 up around the 25ppm mark in my tank and use a pressurised system with digital controller to achieve this. The graph also shows the typical ambient CO2 level, that is the level without injecting any external CO2 to the tank, which is typically around the 2.5 to 4ppm level.
Hope you find the above useful.:)
Cheers