Thanks much for the update and offer! We just somewhat unexpectedly re-roofed the house, did a front brake job on my wife's car, and are heading to CLT next week for a few days to visit some of her friends. Oh, and there's that whole RODI thing I gotta solve. So I'm going to have to forego this round unfortunately.
Question for you guys on water chemistry. This is an odd one. All in all, everything is going great. Immeasurable nitrogen compounds & phosphates. 9.5dKH. About 375mg/mL of calcium (lower than ideal, but should be solved relatively soon). 1300mg/mL of magnesium. pH, of course, swings a bit at night but is holding relatively steady between 8.09 and 8.20. Last week I changed out the Rox carbon, bag of Purigen, and filter floss in my media basket. And as soon as I did that, the pH shot WAY up to like 8.45. It was alarming to say the least, to watch it rise from about 8.2 almost immediately after reinserting the media basket. Any thoughts about what in the world could have caused that spike?!? I rinsed everything off like I normally do in RO water. Same filter floss I've always used (actually cut off the same sheet). Same brand of carbon (BRS) but it was a freshly-opened container. I've gone through this same routine probably three other times and saw absolutely no change in pH whatsoever, as expected. Any thoughts at all about what might have caused the pH to spike??? Luckily the livestock didn't seem to care and I got it back down to around 8.25 by adding 8mL of distilled white vinegar to the top of the media basket and it's been fine ever since. Normally I wouldn't try to buffer the pH suddenly with a "supplement" but in this case I was really concerned about the incredibly sudden, dramatic spike caused somehow by changing the filter media and wanted to try and get it back down close to where it had been just as quickly as it had risen.
I did wait about ten minutes before dosing the vinegar to see if maybe physically moving the basket had dislodged a clump of precipitated kalkwasser powder that might have gotten somehow jammed up in the sump and then stuck to the bottom of the probe or something equally crazy, but the pH showed absolutely no signs of getting back to normal on its own! I realize that's exceptionally highly unlikely - if not entirely impossible - but didn't want to go screwing around with the water chemistry if it was really just a faulty measurement.
This is really the first minor cause for concern I've had yet, and what really bothers me is that I have absolutely no clue what I did while changing the filter media to impact the pH *at all*. Anything else you guys can think of that I might have overlooked??