Conditions at the Grotto



At this latitude, ground temperatures near the surface average 21°-22° C/72°-73° F; these are the temperatures one expects to find in most of the nearby springs. Temperatures at the Grotto, however, tend to be lower, ranging from 19°-20° C/68°-69° F at depth. This necessitates a minimum of a 6.5-7.0 mm wet suit a with hood; dry suits are all but essential at depths below 30 m/100 ft, and can substantially increase your enjoyment in shallower water.

Water flow can vary greatly at Florida’s many natural springs. For example, due to their proximity to the Suwannee and Santa Fe Rivers, springs in nearby Gilchrist and Suwannee Counties can pump out millions of gallons of water a day. In contrast, groundwater flow here in Marion County is often barely detectable.

Duck Weed

This means that the visibility in the Grotto is subject to factors such as local rain fall and algae bloom. Fortunately, the Grotto is protected from the latter by a surface layer of duck weed, a chopped-salad-like plant growth that helps prevent sunlight from penetrating and, thus, inhibits algae growth.


Even though the duck weed performs a valuable function, no one really wants to emerge from a dive, covered from head to toe with hundreds of tiny green seeds. Nor do they have to. Mounted below the surface of the Grotto are a series of low-pressure bubbler vents. We turn these on before divers enter the water and, within minutes, the air bubbles create a large, duck-weed-free zone at the surface of the water.

Bubbler at Work

Despite the presence of duck weed, visibility at the Grotto is generally not as good as one finds at surrounding dive sites, ranging from a normal high of 12 m/45 ft to, on rare occasions, a body’s length or less. At many dive sites, this lack of stellar visibility would limit the property’s commercial appeal. At the Grotto, however, it actually works to our benefit.

U/W Navigation

The real-world conditions divers find in the Grotto can help better prepare them for diving close to home, in local lakes and quarries, the Great Lakes, Atlantic coast and similar sites around the world.