[MTK46]

Larry as dry water softener is had to find I use the liquid stuff. I buy the cheapest I can find. Same way with the laundry detergent. $3.99 for 200 oz of softener at the 99 cent store here. 99 cents for a gallon of detergent. In a old clean gallon coolant container I put 8 oz of detergent 16 oz of softener and add warm water. Shake it up and pore into the toilet. Add 8 oz of bleach and then flush.
No smell problem and like you say the softener helps from build up in the tank. It's cheap and it works. Nothing in it to harm septic tanks.