Thoughts on Using Soda Ash and Spectralite Instead of Iron and Lime in Making a Dye Vat

Q: I see that your Natural Indigo & Shibori Dye Kit uses, and most of your literature refers to using, Iron (Ferrous Sulfate) and Slaked Lime (Calcium Hydroxide) as the reducing agent and pH balancer to create a vat, do you have any thoughts on using Soda Ash and Spectralite instead? Is there a reason you prefer Iron and Lime?

A: Soda Ash and Spectralite have similar effects to the Iron and Lime I use but are not interchangeable for each other. The challenge that I've had with Spectralite is that it cannot maintain the health of a vat for any substantial amount of time and requires refreshing daily (or multiple times daily if dyeing lots of yardage). Also, the excess can build up in the vat and create challenges for you to achieve deep shades of indigo.