Since I never took chemistry in college my understanding of pH is a tad weak so please fill in the gaps. The "number" of a pH basically has to do with a concentration of hydrogen ions, etc etc etc... basically pH 7 has 10^-7 where as a pH of 8.3 has 10^-8.3 concentration correct? So if I add limewater (pH 12.3?) of a certain quantity (lets just say 1 gallon worth to keep numbers simple) to 199 gallons of water at a pH 8.0 then it should go to reason (ignoring localized pH spikes of course), that the ending pH is log ((1* 10^-12.3 + 199 * 10^-8) / 200 ) will give me my pH (basically I'm taking a weighted average of the actual concentration) Which looks like 8.002 which kinda sorta makes sense from a mathematical sense since i'm really adding very little to a large volume (0.5%) however, the overall number makes me think that's actually quite low. The other side of this coin is that if I did the same thing with an acid (say vinegar) where the concentration of hydrogen ions swings more the other way, then my pH would crash to something like 4.7 (which equally seems wrong). So like I said... I need a chemist, who can tell me how to calculate the pH swings. Then as an aside, where exactly do the hydrogen ions go? Since even if I spiked my pH over time it would drop back down, is there any quick and easy formula to figure out the rate of ph drop?