QUESTION: Can you use nitrox in your diluent tank?


  1. When working on a Hollywood set that was 15 feet deep, I actually filled both the oxygen and diluent tanks with oxygen. It prevented a lot of potential issues the actors could have experienced. But let’s consider the best recipe for diluent. First, it must be breathable at your planned maximum depth. Ideally, it should NOT match the PO2 of planned setpoint for maximum depth. You need your diluent to serve several purposes.
  2. Safe open circuit bailout
  3. Diluent flush to confirm sensors – you want to see some movement when you flush
  4. Capable of flushing loop upward or downward when hypoxia or hyperoxia is detected.

With those needs in mind, there is no reason why you can’t safely use an appropriate nitrox blend in a diluent tank. The shallower you dive, the more useful a rich mix may be for flushing a loop upward in the case of hypoxia and for conserving oxygen in your other tank.