Yet another major area of difference between recreational diving equipment and cave diving equipment is the use of weight. In short: recreational divers use weight; cave divers do not. The reason cave divers do not use weight is simple enough. Their tanks and other equipment is already so heavy, no additional ballast is needed.
Recreational divers, in contrast, almost always need at least some lead to offset their bodies’ natural buoyancy, plus the additional buoyancy created by wetsuits, nearly-empty aluminum scuba cylinders and other equipment. The problem is, recreational divers tend to carry far more weight than they really need, and they carry it in the wrong place.
The most weight any recreational diver needs is enough to ensure that, with 500 to 1,000 psi remaining in their tanks, they can hover effortlessly at safety stop depth with no air in their BCs. When divers carry more weight than this, a variety of problems occur:
Recreational divers can benefit by learning to use less weight, and by carrying it in a position that is closer to their bodies’ natural balance point — such as the weight pockets on most integrated-weight BCs. Cave divers may be able to do little to reduce the shear weight of their equipment; however, they do have the advantage of this weight being centered higher on their bodies. As a result, it is easier for cave divers to maintain an ideal, perfectly horizontal body position.