If you are thinking of Dolphinhouse Reef that is about 45 minutes from El gouna - we have dived itseveral times - lovely spot, and have even seen Dolphins there once or twice.

All of the dive companies visit it on a regular basis - and many accept Snorkellers on the dive boats. Not sure specifically about snorkellers only trips - but I should think it likely. We use http://www.divetribe.com (based at the movenpick, but provide transport from all El Gouna hotels) - you might like to check out their website.