6.8 is as low as the PS234 measures, add a little borax to get that number up to a safe 7.0, low pH is needed for the sequestering chem, so don't over dose it - but the pool is being harmed by the acidic water. Then add the sequestering chem, as per label instructions and then, once the metal is 'out of the way' you can add the chlorine and get the other #s in order