Here are additional safe diving practices that you should follow.
You can get DCS more easily at altitude (300 meters/990 feet and above) than at sea level. This is because you are under less pressure at altitude. The nitrogen gas pressure differential in your body is larger than the outside pressure when exiting the water at altitude. The difference in pressure may cause bubbles to expand more than they would at sea level.
When dive planning at altitude, remember to set the PDC, if required, for the correct altitude. (Most modern PDCs do this automatically.) Read the manufacturer’s specifications and instructions carefully so you understand how the PDC works before use.
Flying to Altitude
Follow the time-to-fly reading on your PDC. If the PDC is not working after and/or during dives, it is recommended to wait a minimum of 12 hours from the time of your last dive before flying. This recommendation is for a single no-decompression dive. For a repetitive multi-day trip or decompression dive, wait at least 24 hours before flying.
Driving to Altitude
Be conservative: The longer you wait after a dive, the lower the risk. It is recommended to follow the time-to-fly reading on your PDC before driving to altitude. However, there is insufficient data on this topic; therefore, there are no general recommendations.
Cold and Strenuous Dives
If you get very cold on a dive or if you have a strenuous dive, you may end up with more nitrogen in your body. Your PDC cannot monitor each person’s physical conditions. Therefore, dive conservatively, and when cold, control your ascents and add more dive time at the safety stops. Don’t dive again until you are completely warmed up.
Don’t Dive if You Are Sick
If you are sick, it is not a good idea to dive. You won’t enjoy it as much, and you could put yourself in danger. It is important not to dive with a cold or to allow a person who suffers from asthma to dive. Air can be trapped by airway blockages, which can cause lung overexpansion and possibly gas emboli in the bloodstream. This could cause serious problems for the diver.
Don’t Dive Too Deep
Stay within the limits of your certification. For example, as an Open Water 20 diver, your depth limit is 20 meters/66 feet. The depth limit is in place for your own safety. If you wish to go deeper, you can enroll in additional training programs. Note: The maximum recreational dive limit is 40 meters/130 feet. Any diving deeper than 40 meters/130 feet would be considered technical diving, and you need to obtain proper training, equipment, and experience to venture to depths greater than 40 meters/130 feet.
Don’t Dive With Malfunctioning Equipment
Make sure an authorized technician services your equipment regularly. Properly functioning equipment is crucial in scuba diving. Scuba equipment must be in good working order and respected. Remember that it is life-support equipment.
Don't Go Beyond Your Training
This goes back to attitude and ego! If you want to do decompression dives or to go into overhead environments, work toward a goal with the correct training and gain experience slowly. Open water divers with far more experience than you have—even open water instructors—have died trying to dive deep or swimming into an overhead environment, such as a cave or inside a shipwreck.
Log Your Dives
Keep an accurate record of diving locations, sights, and the important data about the dives. Make your logbook your scuba diving diary. List the marine animals you have seen and anything unusual about the dive. List your equipment used, along with how much weight you used, which will prove handy when re-entering similar environments in the future. The logbook is great to look back on.