Scuba Diving International (SDI) Computer Nitrox Practice Exam 2025 - Free Nitrox Certification Practice Questions and Study Guide

The two most important pieces of information that appear on a Nitrox fill tag or label are the Nitrox mixture used in the tank and its Maximum Operating Depth (MOD).

Understanding the Nitrox mixture is crucial because it indicates the specific oxygen and nitrogen content of the gas in the tank, which directly influences the dive plan and safety protocols a diver must follow. The percentage of oxygen affects the risk of oxygen toxicity at certain depths, making it essential for divers to know the exact mixture they are using.

The Maximum Operating Depth (MOD) is equally important as it provides the maximum depth at which the given Nitrox mixture can be safely used without exceeding the Partial Pressure of Oxygen (PPO2) limits. Staying within the MOD ensures that divers minimize their risk for oxygen toxicity and enhances their overall safety during dives. Each diver needs to have this information easily accessible to ensure safe diving practices.

While the fill date and diver name might be relevant for tracking and administrative purposes, they do not directly impact the immediate safety and dive parameters as the Nitrox mixture and MOD do.