Well done getting a custom report. Your figures are a bit different to mine. I got a reply from one of the water engineers at council who advised that central Nowra where I live (Osborne Street) could be supplied by either Flatrock or Bamarang but that, regardless, their figures are consistently much the same. He gave me a chloride figure but said they don't measure alkalinity or bicarbonate. Ca: 24, Mg: 5, Na:13, Cl: 43, SO4: 27, pH: 7.7. I'll plug in the HCO3 and CO3 you are using and see how it goes. Cheers. Would be nice to share a brew one day when all this social distancing is done. I'm sure I could use a few hints!