Just to clarifiy what Pooldv said:It is safe to swim when:
PH is 7.2 to 7.8
FC is above minimum and below shock level for your CYA
Water is clear
So test FC in another hour, let the CYA continue to dissolve and trust it is there. The fact your. FC was 17 an hour later is good. Generally, you need to worry about CYA falling if you've had to add a lot of water. It doesn't evaporate out hence how it keeps the FC stabilized.
[emoji176] Lisa P.
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