I have Aqulung Titan regulator. Documentation with it says not to use with enriched air. Why? Must I buy new one? Actually, I got nitrox certified and dove for a week. instructor didn't say anything. Discovered it when I got back home.

generally, most regs are good to 40% O2. Also, most shops use an O2 rated lube anyway. You can have your reg checked and cleaned for O2, and consider it your regualr annual service.

Additional techie details is that the o-rings used when the reg was manufactured are rated for long term use with regular air.

When you upgrade a setup for nitrox (or higher O2 percentages for deco staging) the O-rings are changed out for ones that are of a different material.

Has something to do with the enriched air causing faster deterioration of the standard air o-rings.

There are many opinions on this subject. A lot of regulators are set up for up to 40%. These regulators will specifically say they are "Nitrox Compatible to 40%" such as the IDI Searia regulators.
Most regulators that say not to use with nitrox will void the warranty if you do because of the faster breaking down of standard O-Rings.
My opinion on this is(and im sure a few will disagree):
1. Dive with it as is and don't miss your yearly service because you will want to have the o-rings changed at least once a year.
2. you can't handle 1&2 get it O2 cleaned and designate it as your nitrox regulator.

[This message has been edited by Rebecca (edited 09-22-2001).]