Yes, it is normal for the blood pressure to go low during the Phase 2. But 104/68 is not such a biggie. In fact, its close to what many doctors use as a target blood pressure level for the patients i.e. 110/70. Unless you have any unusual symptoms such as dizzyness, light-headedness, nausea or fatigue, you need not do anything about it.
If you start to experiencing any such symptoms, you can bring the blood pressure up by adding some salt to your water throughout the day.