Nice thread. Recently I installed a Trident to monitor the "big three" (ha, trident, took me a bit to get the name). I was surprise at just how much I was driving diel Alk changes by adding ATO with kalkwasser only if the pH dropped below 8.1 or so (I was trying to keep 8 < pH < 8.3). The fluctuations in Alk were so large (~0.8 dKH) that it started causing some problems with the Trident, as I noticed on several occasions that the Trident took double samples. Turns out, if a current measurement differs too much from the previous one, then the Trident considers it in error and will resample. Big fluctuations in Alk will caused the issue. Anyway, I stopped constraining the ATO+kalkwasser additions to control pH, and I increased my Alk operating conditions (I was running closer to 2.3-2.5 mEq/L (6.5-7 dKH) that is in natural seawater, but now run closer to 8.5 dKH). The definition of alkalinity is it buffering capacity, so higher Alk will result in lower pH swings.
I also got briefly interested in natural fluctuation observed in Alk and pH, and found this article, which relates to this thread, but it is for microcosm systems https://peerj.com/articles/378/ but it may be of interest to some here.
I also got briefly interested in natural fluctuation observed in Alk and pH, and found this article, which relates to this thread, but it is for microcosm systems https://peerj.com/articles/378/ but it may be of interest to some here.