Thickness of exposure gear, how new it is, the water you are in, and other equipment used all are HUGE variables in weighting. In our LDS pool, with a 72 cu ft tank diving in swimwear only I use no weight. In the ocean with a full 3 mil wet suit and 80 cu ft aluminum tank I use 12 to 14 pounds, depending on my present weight, which varies). A new wet suit will cause me to add about 2 pounds until it has had 25 hours or so under water, and breaks down a little. Always do a weight check and get properly weighted when diving with new gear and in a new environment. I note all the variables impacting weighting in my log book and have a data base from it for proper weighting in different locations and gear set ups. Also, other equipment can impact weighting. Many lights are the equivalent of adding 1/4 to a full pound of weight, as are many camera and videos set ups. Weight your self in accordance with the gear you are carrying on each dive.
DivemasterDennis