Pool Water Chemistry Log
Free pool water chemistry log (Excel): one sheet per pool for FC, pH, alkalinity, CYA, calcium and salt, with an ideal-range band and a chemicals-added column.
How this log works / what the bands mean
This is a blank record sheet, not a calculator. One sheet covers one pool; you write one row per test date: date, time, water temp, and the readings for free chlorine (FC), pH, total alkalinity (TA), cyanuric acid (CYA), calcium hardness (CH) and, for saltwater pools, salt, plus the chemicals you added and a note. It computes nothing: no dose, no in-range score, no average.
The reference band printed above the grid shows each parameter's typical residential target: it is a printed guide, not a compliance standard and not an automatic pass/fail check. Free chlorine's ideal band is 2–4 ppm; the separate 1 ppm figure below it is the CDC operating minimum for public pools, which is a different thing: an operating floor, not the ideal target.
Choose Spa and two columns join the grid: Last drain and refill date and TDS vs fill water. Total dissolved solids climb as chemicals go in, water evaporates and bathers leave oils, lotions and waste behind, and the simplest remedy is often a partial or full drain. So a spa log dates the water now in the tub and keeps today's TDS beside the fill water's own TDS from that refill, which is what the drain triggers are measured against: drain once TDS runs 1,500 ppm or more above the fill water, or once the days since the last drain reach the water replacement interval (the Spa edition prints the full rule above the grid). The log prints these triggers; it works out no interval for you.
The °F/°C and gal/L toggles only relabel the printed column and header and convert no value. You write the reading in whichever unit you chose. To turn a reading into a chemical dose, hand the numbers to the pool chemical dosing calculator or, for the sanitizer column alone, the chlorine dose calculator; this log deliberately does not do dosing math.
Two columns are worth reading together. Total chlorine minus free chlorine is combined chlorine, and a log that shows it creeping week after week is the signal to stop topping up and run the much larger oxidizing dose sized on the breakpoint chlorination calculator. A public or commercial venue keeps a heavier record than this one, a page a day rather than a row a week, which is what the commercial pool daily log sheet is laid out for.
Nothing is saved. There is no stored history, no roster, and no cross-session state: every value lives in the file you download or on the printout.
Sources
- Pool Water Test Log (printable + Excel). Pool Shark H2O. Retrieved .
- Operating and Managing Public Pools, Hot Tubs and Splash Pads: minimum free chlorine 1 ppm in a pool and 3 ppm in a hot tub, hot tub pH 7.0 to 7.8, "Test pH and disinfectant levels at least twice per day", and for hot tubs "Drain and replace all or portions of the water on a weekly to monthly basis, depending on usage and water quality". U.S. Centers for Disease Control and Prevention. Retrieved .
- Total dissolved solids: Explained (PHTA Recreational Water Quality Committee, 3 August 2020), reproducing ANSI/APSP/ICC-5 2011: drain a spa when "TDS in the spa exceeds the source water TDS by 1,500 ppm or more", or when the water replacement interval, 0.33 × spa volume in gallons ÷ maximum bathers per day since the last change, is less than or equal to the days since the last drain. International Code Council, Building Safety Journal. Retrieved .