Enough washing powder for 20 washes. No need to increase the amount for hard water. You chose the soap element whch make this a unique product.
Just Primal Ecological Washing Powder 1kg
This washing powder has been trialled and tested over a number of years to make sure it does what it needs to do: be gentle on your clothes and therefore your skin, soften the water to maximise the benefits of the soap, and to help with maintaining your washing machine. No other washing powder does that!