The pH of the water is generally agreed to be most affective at around 3, but temperature and length of time vary considerable between labs (ranges between around 70'C to 120'C for 1/2 to 18 hours).
(The pH of the water; to be; most affective; T:at around 3) (temperature and length of time; vary; considerable)
The pH of the water temperature and length of time
to be vary
most affective T:at around 3
considerable