Buoyancy in salt water pool

[ScubaSteve1962]

Would the buoyancy check in a salt water pool be the same as an ocean dive, or fresh water dive.

 

[CT Sean]

If the salinity level is the same as the ocean, yes your buoyancy would be the same. If the salt water pool actually IS ocean water, then again, buoyancy will be the same

 

[spectrum]

You need to know what salinity / specific gravity they are maintiaing. One local shop claiming salt water is 50% of typical ocean conditions.

Pete

 

[knotical]

Most saltwater pools are only about 1/10th the salinity of the ocean.

 

[TMHeimer]

I believe there is other stuff in ocean water (suspended) that would affect buoyancy, splitting hairs.

 

[Insta-Gator]

The salt used in pools actually passes through a device next to the filtration system that converts it to clorine on a regulated basis. The pool guy said that the salinity of a salt water pool is about the same as a human tear. So if you're checking buoyancy, figure you are in fresh water.

 

[dmoore19]

Sea water is around 3.5% mostly sodium chloride. Tears from your eyes around .9%. From what I understand the salinity of salt water swimming pools varies anywhere from .28% to .4%. The Specific gravity of seawater is approximately 1.025 g/ml (8.553ppg) with the Specific gravity of the salt water pool being 1.0022 g/ml (8.363 ppg) to 1.0029 g/ml (8.369ppg). Fresh water has a specific gravity of 1.0000 g/ml (8.3456459ppg). So I would guess the weighting in a salt water swimming pool is going to be much closer to fresh water than sea water. The difference between fresh water and a salt water swimming pool is negligible.

 

[DivemasterDennis]

I think dmoore19 has it right. What is most important to emphasize on this thread is that you do a buoyancy check and weight yourself properly in each new environment in which you dive. Salinity of the water, the exposure gear you are wearing, and the equipment used (aluminum vs steel tank, bc model, other gear carried). Salinity of the ocean varies place to place and sometimes within one place from season to season. I keep a note of weighting and equipment for each dive location we have been, and it simplifies weighting. But we still do a check on the first dive as at destination, as even the age of the exposure gear worn affects its buoyancy and thus proper weighting.
DivemasterDennis scubasnobs.com

 

[TMHeimer]

I just saw on TV they use "Instant Ocean" for the big aquarium in Atlanta. It has all the trace elements in real sea water. That may be the difference from a salt water pool.

 

[dmoore19]

I just saw on TV they use "Instant Ocean" for the big aquarium in Atlanta. It has all the trace elements in real sea water. That may be the difference from a salt water pool.

Having had a salt water aquarium at one time, there are several different brands of "instant Ocean". You mix the stuff with water and adjust the salinity of it to match that of the ocean.

There are a lot of different salts in ocean water, the main one being NaCL. There is also minor amounts of KCL, CaCL2 and others in ocean water. A salt water pool doesn't have nearly as much salt in it as the ocean. Salt is a dissolved solid and adds density. Sodium Chloride brine is saturated at +/- 26% with a SG of 1.1993 (10.0 ppg) Other salts such as Calcium chloride saturate at +/- 40% with a SG of 1.3982 (11.66 ppg). Might not be relevant to this thread but it gives an idea about the variance in density with concentrations of different salts can be achieved. It can vary a lot dependent on the concentration and kind of salt used.