Originally Posted by Delapool
Would the ph/kh
chart still work though as it is basically a mathematical formula?
If it doesn't work, would you know what causes it to be wrong in SW
This is just for interest to see if the chart is any more reliable in SW
. For example I'm assuming driftwood is not commonly added in SW
The chart does not care what type if water is involved. It is using a specific value of alkalinity. Whether the alkalinity is affected by calcium carbonate or sodium bicarbonate is irrelevant. The equation states that at that particular kh
level with this particular ph level (only altered by carbonic acid) the carbon dioxide level will be X. The chart uses that formula right across the board.
When we take the chart across to use in saltwater or freshwater the values become meaning less because the conditions required to get the scientifically and mathematically correct answer for co2
do not exist.
The chart therefore cannot be used reliably in any setup. It is the ph value that really matters though. The chart doesn't care what kind of buffers are present because they all contribute to the measured alkalinity value. What is important is the things that are present that directly alter the ph level. For example, like you say the addition of driftwood. The chart is not taking tannic acid in to consideration during the calculation and it is impossible to subtract the ph difference caused by tannic acid. Tannic acid is just one example, there my be others.
In turn the ph value becomes unreliable for the equation because there are other factors affecting it.
The problem we face is determining kh
. How accurate is the kit used for this? Already we have discrepancies and tolerance.
The chart can only be used as a very rough guide as far as I understand.
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