Stabilizer Mystery

[chem geek]

In any case, the higher the pH, the greater the propensity to form monochloramine preferentially over other species. (So, add borax!)

Just FYI: monochloramine forms almost immediately (in less than a minute in pools with recommended FC/CYA amounts) when chlorine combines with ammonia and this happens at all pH levels. Higher pH levels tend to produce more trihalomethanes (e.g. chloroform) when chlorine oxidizes some organics (those that have or end up with methyl ketone groups) while lower pH levels tend to produce more nitrogen trichloride from multiple substitution with ammonia and partial oxidation of urea (i.e. it is a disinfection by-product). Generally speaking, at the low active chlorine levels in pools with CYA and the low bather-loads in residential pools, I wouldn't worry about either.