Dye Geek: using water softener

Metaphos added to soda ash solution in varying amounts

Over the years I’ve accumulated a whupload of dye trivia. Included in that is “how much water softener should I use?” In this case, I’m referring to Metaphos (Pro Chem’s name) AKA Sodium Hexametaphosphate (the chemical’s and Dharma’s name.) One source instructs us to use 1/2 gram per liter, and another says 1-1/2 grams per liter. So I pulled out my gram scale and liter cylinder and made four samples, shown at left. I’m saving these for teaching, too!

To elaborate, these bottles all contain soda ash solution mixed at 1/2 cup of soda ash to one gallon of water, which is also two tablespoons per quart/liter. The first bottle contains no water softener; the second has 1/2 gram per liter; the third has 1 gram per liter; the fourth has 1-1/2 grams per liter. 1 gram per liter wins in my book, and that translates to 1/2 teaspoon per gallon.

Next questions to answer:
*if I make my soda ash concentrate stronger, as I do when dyeing in the washing machine, does it require more water softener?
*will I see a difference if I mix my dye with water that includes softener?

Of course, it has taken since October for me to actually run this test, and it’s been in my head for years! Maybe if I make a list of experiments to complete, I’ll actually DO IT!

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