## Trimix family : Hypoxic Trimix Less popular than [Normoxic trimix](Normoxic%20trimix.md) and [Hyperoxic trimix](Hyperoxic%20trimix.md) in the [Trimix](Trimix.md) family, the hypoxic trimix is oxygen-depleted. This one is concentrated at an oxygen content lower than 18%, then we adjust the balance between helium and nitrogen in order to achieve a specific dive. Hypoxic trimix isn't breathable in surface. This means that the diver need to have a specific tank with this mix in addition to his normal mix. \(Or to dive with a rebreather that will create gas mixes automatically, but this is another story\). It is used to go deeper than -60 m. Here's how divers are switching gas underwater: <iframe width="100%" height="515" src="https://www.youtube.com/embed/ATfl-ou2_Yc" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>