<a href=showthread.php?s=&postid=9913129#post9913129 target=_blank>Originally posted</a> by Boomer
Stony
There is some anecdotal experience that higher levels of alk can cause RTN.
Yes, that is true, so call it "Alkalinity Burning" and may be to do with the higher OH-
Sure there'd be higher levels of CO2 but at higher pH would they all be bicarbonates?
No, as pH rises the bicarb is less and there is a rise in the carbonate with even less CO2 % wise. Bicarb is the highest % a pH of lower than 7.5 and steadily drops as pH goes up, being replaced by carbonate at higher pH's
With that said the question you have is for example;
pH 8.3, Alk 2.5 meq / = 0.42 ppm CO2 NSW
Ok lets just raise the pH to 8.5 = .23 ppm CO2
Now lets have that high pH of 8.5 and raise the Alk to 5 meq/ l= 0.46 ppm CO2. The same as NSW
Now lets keep that more normal pH of 8.3 and raise the Alk to 5 meq / l = .85 ppm CO2 almost double NSW.
If we go with the max Alk of 3.93 meq / l (11 dKH) and pH of 8.3 = 0.66 ppm CO2 or 65 % higher than NSW. [/B]