Agiflow,
If you have hard water your best bet would be to secure some real STPP (Sodium TriPolyPhosphate) and add an tablespoon or more as needed to soften the water.
The slick feeling of the water comes from alkalinity. Alkalinity helps to deal with fatty soils, but is not absolutely required for cleaning. For example, detergents for silks and wools are neutral, not alkaline. STPP will however make the water slick but it's milder than the usual alkalinity agent, Sodium carbonate, in most powders.