Here's a few shots from the trip, including:
A view of the lake on our descent in the car from the peak of the crater:
View attachment 29034
A small island (the top of an underwater mountain) formed during the last major eruption in the late 1800's. This was also the site of one of the dives:
View attachment 29035
One of the sites had underwater hot springs all over the place, sourced from long thin fissures. There's a "vapor" effect from the change in temperature, you can see this in the "wavy hand" photo below. The springs are like bath-water temperature. In some other spots, there's no springs and you don't feel any change in water temperature, but if you stick your hands into the sandy/gravelly bottom you can definitely feel the warmth.
View attachment 29039
I'm pretty proud of this one, this is one of my best UW animal photos ever (if I do say so myself). We saw quite a few of these crabs down there.
View attachment 29041
Not a great photo, but it gives you an idea of some of the other life down there (small fish) as well as the typical UW terrain (rocky). Also, not shown in this photo, there are fresh-water sponges and algae growing on some of the rocks near the surface -- the algae looks like a red carpet, and is covered with small bubbles from the oxygen it makes.
View attachment 29042
Thanks again to Alex at El Salvador Divers. I definitely recommend giving them a call if you're in town. In addition to Lake Ilopango, they also make regular trips to the El Salvador coast (Los Cobanos is a popular dive site, too bad we didn't have the time for that one) as well as occasional trips to Roatan and other international locations.