when you say natural reefs, I assume you mean warm water, giant reef tank... right? If you have an open mind come on out to So Cal, absolute beautiful diving, just a bit cooler than you are probably thinking. We have San Diego, Catalina, Channel Islands (Cousteau listed the islands in the top 10 places in the world to dive) We have giant kelp which is only found in two places in the entire world, if you dont come here, you have to go to Australia/New Zealand to see it. We have the Garibaldi, think of giant bright orange damsel fish that will get right in your face. If you dont mind water cooler than high 70s, seriously come out here for some diving!