Fresh vs. Salt water weights

[Raiderswim]

Going to Florida and need advice on weights.  Water temp is 62 so I'm leaning toward the 7 mil.  In fresh water, I use 18lbs with a 7mil.

In Salt water, I use 14 with a 3mil.

How much more buoyant is salt water?  What would be a good weight.  Any formulas out there?

Thanks

[jasondbaker]

I've heard some rough formulas based on your body weight. For example, one formula proposes that the diver wears 5% of their body weight.  These are only rough estimates because the amount of weight required can vary significantly depending on the exposure suit, tank size, BC type, body mass, diver experience level, and salt or fresh water. 

If you know your freshwater weight requirements in a given exposure suit/BC/tank configuration you should plan to add a couple more pounds for salt water diving. 

Equipment can make a big difference though.  When I dive in salt water with a regular jacket BC and full 3mm suit I need 8-10lbs of lead.  When I dive with an aluminum backplate+wing I only need 3lbs. I'm 6-2", 195lbs. 

[Raiderswim]

Its the same configuartion, BC, tank, etc.  Just going from fresh to salt. 

[arcFlash]

3% more according to the math.

Everyone weights different so it's just something you need to work out. Guess from what you know works and add/remove 3%. I would caution about over-weighting (just to be sure) as that creates so many other issues. Guess well and go, adjust next dive.

[Deep Thought]

Diving has always been a sport with formulas, acronyms and idioms…which have been passed on for generations without any clear reference to who created them or if they are even valid.  Like the concept of ascending with the smallest bubble, to proper weighting is to calculate 10% of a divers body weight plus 5 lbs, the origin is vague at best.  The concept of determining lead weight is relative to the water Salt/Fresh as well as the Exposure Suit, and SCUBA equipment.  When you consider that the majority of divers, dive in salt water and historically it was a ¼ neoprene wetsuit/boot/hood with a steel 72 cu. ft. cylinder, then it fits an ocean diver.  The 10% formula, or 10% + 5 still works fairly well with an aluminum 80 and 7 mm suit in the ocean, and obviously needs to be modified with thinner suits or addition of dry suit.

[arcFlash]

I'm agreeing with the post but the bubble isn't totally lost to history. It's out of date with modern models but fits the idiom.

Math warning. (there is a chart as well)

[Adam6521]

Jump in and find out!!