Thanks Steve, I will try reducing my 170 ppm water with 0.2ml/L phosphoric acid. Will do a 5 Litre sample with 1 ml of phosphoric acid and see what I get.I think from Bru'n Water 0.1ml/L removes about 60ppm alkalinity.
If you have the KH test kit it might be worth testing that to confirm.
Thanks that roughly tallies up with Steves 0.1ml/L removing 60ppm.I don't know if this will be of any help here, but at somewhere right near 73.5% concentration, Phosphoric Acid can quite effectively use data commonly seen for 88% Lactic Acid. At 75% you are not far off from this.
Likewise, Phosphoric Acid at 68% can utilize data seen for 80% Lactic Acid.