This will be our first year using a septic system we had installed at our cabin. 1. What do you use to clean the toilets/shower. I assume we shouldn't use bleach because it will kill bacteria in the tank. 2. We had a couple of the tank blankets laid down on the septic tank for insullation. We will also keep from packing down the snow on the tank and drainfield. What else should be done to prevent freezing? (especially with the pvc pipe carrying waste to the tank.) 3. How much rv anti freeze to put in the toilet and tank when we leave it unoccupied for a while? Any other helpful hints?