Causes of poor visibility in cave diving
Bad visibility and cloudiness in the cave can be caused by various factors, such as the size of sediments and mud, irregular or sloppy fins, the rainy season or floods. The larger and heavier the deposit is, the faster it settles on the bottom of the cave. The easier and smaller the deposits are, the more time it takes to fully subsidence and restore visibility.
Sand, clay, mud, sludge, sediments and decomposed organics make up most of the layer covering the floor of the cave. Also, bacteria can grow in the caves. One wrong move can easily lead to a complete drop in visibility within seconds.
Diver faces the danger of raising sediments, using the wrong swimming technique, dragging the equipment along the floor of the cave, touching the floor or walls, or knocking off the deposits from the ceiling with bubbles. Sometimes all this happens simultaneously.
Also, some chemical compounds, for example, hydrogen sulphide, can be found in the caves, which usually looks like a white cloud of varying density, smells of rotten eggs, and at high concentrations can cause dizziness in a diver. Tannin of soil color, washed away into the cave by rain, has the same visibility characteristics as tea or coffee. Haloclines are formed in places where fresh and salt water are mixed. The visibility in the halocline layer is usually zero, the diver sees only the blurred outlines through the mask.
Cave systems are underground rivers with their currents. If the current is strong enough, the diver will feel the resistance of the water at the entrance to the cave. Sometimes, if a turbidity has come up at the entrance, the diver can make a choice in favor of waiting until the current clears the suspension, guided by the rules for calculating gas. In caves where there is no current, the silt layer will be thicker, and in case of cloudiness the cloud of deposits will settle for longer. In such caves you should not wait until visibility is restored with the help of the current.