TA 80, CH 280, FC 3, pH 7.5, CYA 50, borate 30.
Two-adult bather load, nighly, every day. Full showers before entering spa, and we get out if we need to urinate.
Water had been completely clear, absolutely pristine.
A few days ago, it acquired a slight translucent look, kind of milky (but colorless).
Shocking it with CL didn't fix anything.
The filter is clean.
The only recent change is that we haven't used it for the past five days because I was traveling and she was busy.