My Cressi Leonardo defaults to recommending a deep stop if you come within 3 minutes of your NDL. I believe you can turn it off, but it doesn't lock you out if you just skip it. I like to keep a minimum 5 minute NDL buffer on my dives, so I'm not very familiar with the feature. I'm skeptical of its value, but the one time I incurred a deep stop, it cleared itself on the way up. I think most rec computers have the option of increased conservatism settings too; mine does.
I'm no expert, but I'm really uncomfortable with the idea of diving Nitrox on air settings if you feel like you need a depth alarm. You want to be really conscious of your depth if you're diving Nitrox at a site where the bottom is below your MOD. It's easy to miss an alarm, especially if you're wearing a hood, and the extra step of setting a depth alarm just adds more failure points in the process. I also really don't like lying to my computer. If I do get bent, or get some DCS-like symptoms that might be something else, I want an accurate record of what just happened. My personal preference for increasing conservatism is:
1) Just stay away from the NDLs. Decide to start your ascent while you still have 5 or 10 minutes remaining or whatever makes you feel comfortable.
1a) Instead of or in addition to the above, do a 5-minute instead of 3-minute safety stop, and take those last 5 meters to the surface as slowly as you possibly can.
2) Use a more conservative setting on your computer. Mine defaults to a "safety factor" of 0; you can increase it to 1 or 2.
3) Dive Nitrox on air setting. Honestly not sure why anyone with a Nitrox-capable computer would choose this instead of 1 or 2.
I'm no expert, but I'm really uncomfortable with the idea of diving Nitrox on air settings if you feel like you need a depth alarm. You want to be really conscious of your depth if you're diving Nitrox at a site where the bottom is below your MOD. It's easy to miss an alarm, especially if you're wearing a hood, and the extra step of setting a depth alarm just adds more failure points in the process. I also really don't like lying to my computer. If I do get bent, or get some DCS-like symptoms that might be something else, I want an accurate record of what just happened. My personal preference for increasing conservatism is:
1) Just stay away from the NDLs. Decide to start your ascent while you still have 5 or 10 minutes remaining or whatever makes you feel comfortable.
1a) Instead of or in addition to the above, do a 5-minute instead of 3-minute safety stop, and take those last 5 meters to the surface as slowly as you possibly can.
2) Use a more conservative setting on your computer. Mine defaults to a "safety factor" of 0; you can increase it to 1 or 2.
3) Dive Nitrox on air setting. Honestly not sure why anyone with a Nitrox-capable computer would choose this instead of 1 or 2.