I have not seen any effect based on pH (power of Hydrogen, aka acidity) values. But such measurements require repeated samples taken over a prolonged period under controlled conditions. However, I know that I am very acidic and I am also highly infested.
Correlation does not mean causation...but I think for some individuals, alkalinity is unattainable. A local gentleman who owned the most progressive natural health food/supplement store in town (pop'n < 200,000), passed 10 years ago of bone cancer, after being in remission for several years...He advocated alkalinity to the end.
In a quest for alkalinity, I could be eating boxes of arm and hammer with my breakfast cereal before my system grants me an alkaline reading. (Eating arm and hammer is NOT recommended)
But I'm freaking when I hear of your children's hair. Satisfy yourself that this is true: Baking soda (NaCO3) in water can't burn them. Hell, it's used as a fire retardant, and is a recommended treatment for minor burns. Known to have appx same toxicity (as measured by LDL) as table salt (NaCl-). See below: a US patent application for disinfecting poultry:
"It is also used medicinally for people for gastric or urinary hyperacidity, and locally as an aqeous cleansing solution (1 to 4%) for mucous membranes and as a saturated solution [two T baking soda/pint h2o] for dressing minor burns. Sodium bicarbonate is also used in the veterinary field of medicine both externally and internally on animals. (reference: The Merck Index; 7th ED)"