Diving Marathon in April

My family is renting a house in Marathon in late March/early April. We would like to dive 2-3 days, but the other families have little recent bottom time so will likely want to snorkel instead of dive. I am looking for recommendations on dive operators which are willing to accomodate both in a single group of 6-10 people, with no more than 3-4divers. Abyss and Tildens both seem to be recommended frequently here - are there others I should consider? I would also appreciate any recommendations on dive sites which can also accomodate snorkelers - obviously the shallower dives. Lastly, it looks like I can expect water temps in the upper 70's that time of year - is that accurate?

Thanks for any advice or help I can get.

You might try one of my favorite boats at Captain Hooks. They are now owned by a family and are very accomodating. They will also take divers and snorkelers at the same time. Tell em Steve sent you....

As for sites, try "stake" (at coffins patch) and donut. Both great for divers and snorks.

I agree on the spots. We did both of them in October.