Been kind of tempted to add a second chamber myself. Seems to me even if chasing pH isn't that big of a deal, if just seeing the media deplete in the second chamber means that you're squeezing more life/function out of the CO2 that is otherwise just going to float away then that's a win in itself.
But I have been kind of wondering if it would be better not to dip so much at night. I recently started dripping kalk in at night as an experiment. (Years and years ago I ran both a kalk stirrer and a calcium reactor and I kind of look back on those days as the glory days of SPS for me and I guess it's sort of my "reef aquarium mid life crisis" that I'm seeking to relive those days, but I digress
). Anyhow so far I can't say I really notice a difference with the pH when the kalk drip is on, but it's only dripping 15 minutes every hour between midnight and 8am so there is room to increase it. But so far it doesn't look like kalk does much to stop the pH dip.
My other thought I've been kind of wondering about is just setting the controller to turn off the CO2 solenoid at night and see what that does. I suppose down the road when my wee little frags aren't quite so wee, that this strategy might mean the reactor won't keep up, but for now it seems dubious to me that there'd be a huge difference in my Ca and Alk #'s if the reactor wasn't at 6.7 for a few hours of the night. Hard to say though.
In the end though if the tank inhabitants look fine enough, does it really matter what the pH does? I remember Brad always would say something like "my tank stopped having pH issues the moment I stopped measuring pH."
Which brings me to my last muse for now, which is my probe that I use on my tank is kaput. My good probe I use for the pH controller but the "bad" or old probe is measuring the tank and just giving me a nice little graph on the controller webpage but it's pretty clear even from the graphs that it needs to be recalibrated on a weekly basis. So then is it worthwhile to spend $80 to replace a probe for a nice little graph, or heck would something like this be a bad idea? (Because it's kind of hard to argue against $8 versus $80 plus shipping??)
http://www.ebay.ca/itm/BNC-Electrode...cAAOSw3KFWb9xT