You said you let your truck sit for long periods. Do you have the diesel tank topped off before you do that or not worry about condensation? Are you worried about diesel life span too?
I'm not sure what I said, ha but it's best to keep it topped off and diesel can go bad and when it does, algae and other issues cause problems in the tank. Keeping it topped off will prevent that. There's additives also but haven't needed them.