Arm and hammer wash soda

[MikeB]

It's not borax. It is all natural and non toxic similar to baking soda but more caustic with a ph of around 12. I have only used in in hard water at a rate of a quarter cup per gallon of water in addition to whatever Chems I'm using.
The only caution I've seen is not getting on aluminum or waxed flooring (unless you're trying to remove the wax)
I can see an obvious improvement in cleaning effectiveness when using it with hard water.