Tanks in 2018 Thor ACE 30.4
The Tanks in the 2018 Thor ACE 30.4 are the Gas Tank, the Fresh Water Tank, the Black Tank, the Grey Tank, and the Propane Tank.
The Gas Tank holds 80 gallons. The Fresh Water Tank holds 50 gallons (Bay 4); the Black Tank holds 40 gallons of nasty stuff (Bay 8); the Grey Tank holds 47 gallons (Bay 8). The Propane Tank holds 88 gallons (Bay 11).
Press buttons on the Control Panel in the Entry, and you will see how full your tanks are. (The Gas Tank displays on the dashboard.)
The 2018 Thor ACE 30.4 has a Black Tank Flush (below two faucet controls to the right). This is an invaluable feature that enables you to truly empty the stuff from the toilet that makes its home in your Black Tank. You simply connect a garden hose from the connection at your campsite to the Black Tank Flush connection in Bay 8. Then do exactly as The RVgeeks explain in this video. Don’t get in a hurry; the waiting time of three minutes is vital to success.
https://www.thervgeeks.com/rv-holding-tank-dumping-1-2-3/
As they say in the video, DO NOT LEAVE YOUR BLACK TANK OPEN.
https://www.thervgeeks.com/dumping-cleaning-an-rv-black-tank/
About GAS: It’s best to keep the Gas Tank at better than 1/2 full. I’m told that’s because the Generator is persnickety.
So, when it comes to Tanks, lots of gas, propane, and fresh water are good. Lots of black water and grey water are not good. Go for GOOD!