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Price history: ₱216 every time we've checked since Oct 29. We'll show changes here.
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Phenol red is an indicator commonly used to measure pH in swimming pool test kits. Available in 15 mL bottle RLJ Phenol red, sometimes labelled with a different name, is used as a pH indicator in home swimming pool test kits. Chlorine can result in the bleaching of the dye in the absence of thiosulfate to inhibit the oxidizing chlorine. High levels of bromine can convert phenol red to bromophenol red(dibromophenol sulfonephthalein, whose lowered pk2 results in an indicator with a range shifted in the acidic direction – water at pH 6.8 will appear to test at 7.5). Even higher levels of bromine (20 ppm) can result in the secondary conversion of bromophenol red to bromophenol blue with an even lower pKa, erroneously giving the impression that the water has an extremely high pH despite being dangerously low.
