Didn't expect my fill water chemistry to swing this much by season

Started by Marcus Reed · · 2 replies
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#1
Topped off about 4 inches this week after the heat, then retested and TA had jumped almost 30 ppm from where it normally lands after a fill. Called the city, turns out they were doing seasonal maintenance on the water treatment side. Never occurred to me that fill water isn't a fixed number, I've been treating it that way for years and just assumed 80 ppm TA and pH around 7.6 was constant out of the hose.

Had to walk pH back down with acid additions I don't normally need this time of year. Nothing dramatic, just an annoying reminder that the baseline you're topping off with isn't static, especially if you're in a city system versus well water. Anyone else actually track their fill water numbers a couple times a year or is everybody just assuming it's the same every time like I was.

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#2
I'd push back a little, city treatment changes are common but so is seasonal source switching, some cities blend well and surface water differently in summer and that alone moves calcium and TA around, not just maintenance events. My fill water sits around 400 calcium most of the year but I've seen it dip some in spring, never bothered tracking pH and TA close like you're describing since acid demand always shows up anyway.
#3
Karen's blend point is a good one, city near me swaps a surface source in during summer for demand reasons and calcium moves because of it, not just chlorination changes. I don't test fill water on a schedule but after any "we're doing maintenance" notice I'll run a quick TA and pH, cheap insurance against fighting your own tap water all week.