As was stated earlier a home septic is not the same as a RV holding tank system. First of all a home septic relies on living bacteria to break down the waste. A holding tank system uses chemicals to break down waste. For that reason you really don't want to add that same chemical to your home septic system because it could kill the living bacteria that breaks down the waste causing very expensive problems.
Just ask your local septic company. That's where I first heard about this and since have read it online somewhere.
I do use a solution of 2 cups laundry detergent, 1 cup water softener, to a gallon of hot water to pour into my black water tank and use just 1 cup softener in the gray water since it already gets soap from showers and washing dishes. This helps with making everything less likely to have waste stick to it as well as reducing the stink. Along with this I still use tank chemical to break down waste. Thats a must.