Name: June
Message: I live in the sandhills of South Carolina -- a high-acid environment -- and our well water, which is our only viable source of water for dyeing, is highly acidic. Should I attempt before dyeing cellulose fibers with Procion MX dyes to bring the dyebath water up to a more neutral pH? If so, do you think I should mix in a small amount of soda ash or is there another chemical that would be better for this process? Thanks!

You are right that it is very important to use the correct pH in dyeing with fiber reactive dye. You may need to use a larger quantity of soda ash. I would recommend it rather than any alternative chemical, however.

The very nice thing about soda ash is that it has a fairly narrow range of pH that it can produce, so that if you put in way too much, the pH will still not be over 12. Ideally, you should use a pH of 10.5 to 11. The simplest way to determine this is to buy some pH paper and check to see how much soda ash you need to use, per unit of water, in order to get the desired pH.

If you are using your dye concentrate solutions the same day, the pH of the water in which you have dissolved the dye probably does not matter much, but for short-term storage (up to a week at room temperature, or longer in the refrigerator), it would be best to bring the water to a neutral pH, around 7, before dissolving the dye in it. Fiber reactive dye tends to degrade faster in water that is basic OR acidic. You could use soda ash (sodium carbonate), or baking soda (sodium bicarbonate, which can produce a pH up to around 8, or a few drops of NaOH if you were working in a lab. If you use a large quantity of baking soda or sodium carbonate, the sodium itself may have some effect on your dyeing.

See "What is the effect of pH in dyeing? " and "Do I need to use salt, in dyeing?".