Fresh water tank is for washing and then it goes i to the grey holding tank.
The black holding tank is for the toilet flush.
Me, I drain the black tank i to the dump station then drain the grey tank into the black tank then i to the dump station. I drain the fresh water tank to the ground and B 4 the next camping trip, I sanitize it with a bleach mixture, flush fill, flush then fill. I do not fill it all the way up due to the weight
. We use it to wash and not to drink. We buy bottled watter, freeze them then put in the fridge
on the day of departure to help keep the fridge
cold and use them to drink.
We put the toilet additive in the black tank. You can get allot of your camper stuff at Walmart at a better price than a camping store.