Halocline (salinity layer)

A halocline is a distinct layer where fresh water meets salt water. This meeting creates a visible boundary in the water column. You will see it as a blurry or shimmering zone because the two liquids have different densities. In places like the cenotes in Mexico, these layers appear clearly between 5 m and 12 m depths. The density change bends light so that your vision becomes distorted. This effect makes it hard to see your gauges or buddy. Do not panic if the water suddenly looks cloudy. Most divers make the mistake of swimming too fast through this layer. Slow down your buoyancy control while you pass through the transition zone. This helps you avoid silt clouds that can ruin visibility.