Can I use castile soap as my laundry soap and add in essential oils?

I used to use Castile soap for my laundry, but due to the hard water in Kelowna, I have found many of our clothes began to smell over time. This happens because Castile soap creates soap scum (soap combined with minerals in the water). After a while, this scum gets caught in the fibers of clothing, which eventually turns rancid, smelly and makes clothes feel heaver (due to the minerals trapped in the cloth fibers).
For a number of years I've been using washing soda (sodium carbonate), which is different than baking soda and combine it with sodium gluconate (fermented sugar). The sodium gluconate acts as a natural chelating agent that binds to minerals and flushes them away. Washing soda is alkaline and keeps clothes clean and fresh smelling.
I have tried using essential oils in my washing machine and dryer, but because the essential oils I use are pure and don't contain chemical fixatives, that other essential oils and/or fragrances/perfumes often use, the scent of the essential oil does not last. The long and short of it is that pure essential oils evaporate very quickly so its impossible for their scent to last when added to laundry. 
For a more detailed answer click here and scroll mid way down.