Draining diesel fuel.
If the book says to drain the fuel every 150 hours, the book is dumb. The only reason to drain fuel is if it has gone bad, which seldom happens. If the tank gets water in it, it can be sucked off the bottom through the top. There is no drain on the 310 tank nor on any of the other plastic tanks in Hunters. Your fuel is constantly being refreshed, every time you add fuel. If you have kept water and additives out of your fuel and purchased good fuel, you shouldn't have any problems.