Good point about the calcium reactor, didn't think about those of you who dose around the clock. seeing an increase of 0.2dkH though makes me wonder how much the consumption is night versus day. I'd guess you have your reactor dialed in such that it may be up in the morning but that gets used up by night time, maybe even beyond used up so that over night you make an excess at night?
Either way, just was idly thinking about it, I don't have a way to graph pH yet, at least one hooked up I have an old AquaController but don't feel like running ethernet to my tank... at least not yet. Plus more importantly I'm still trying to nail down how much kalk per day I should be aiming for. Just found out the other day that my lovely Red Sea test kit syringe does allow for the ink to come off the outside if I have something on my fingers (water? reagent? dunno). So I think I'll be throwing a +/- about 0.2 dkH to my values until I get some new syringes, luckily 1mL syringes are dirt cheap