Using EANx Regulator with Air

[CTA]

Hi -

I will be taking the Enriched Air Diver course from PADI very soon, in preparation for a trip to Belize. I was just reading in a product catalog about using regular air in a regulator that has been cleaned for EANx blends of up to 40%, and it said if you did that, and then wanted to use EANx, you had to first have the regulator cleaned due to the higher oxygen content in the enriched gas. Then when reading more about EANx, and that each blend has a maximum depth, I began wondering how this would be handled on my upcoming trip. I am scheduled to dive the blue hole, which I am told would be around a 120-130 foot dive, which would either require (or so I am deducing based on what I read) a blend less than the normal EANx blends or me to use straight air instead. So then I am wondering if that is the case that I have to use air, will I essentially not be able to use my reg the rest of the trip and be forced to use air, if I want to use the same regulator? If my logic above is correct, I would imagine the dive resorts would have some way to deal with this issue, but I thought I'd ask the experts here. In case you cannot tell, I am a fairly new diver and entirely new to diving with enriched air.

Thanks for any input.