Diving salt water vs fresh water?

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leeblackman

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I understand that one typically needs more weight when diving salt water vs fresh water. What are some other issues that occur between the two? Are there issues in reading depth?
 
No...
 
Maybe JeffG can find the time to explain his outstanding response.
 
Maybe JeffG can find the time to explain his outstanding response.

Its self explanatory. Other than weight required, there is no difference.
 
There are no significant issues with reading depth. However, it should probably be pointed out that dive computers sense pressure and then mathematically convert this number into fsw (feet salt water) or ffw (feet fresh water) for display purposes. The different densities of salt water and fresh water cause their pressure-depth conversion equations to be slightly different. A computer calibrated for fresh water will display a 3% depth error in salt water.

So will this difference affect the way you dive? Probably not. If your dive computer has a special setting for salt or fresh water, by all means use it.

After a dive in salt water, just make sure to do a good rinse of your gear. Salt crystals can affect the operation of regs, BCDs, etc.

Enjoy your dives and be safe.
 
Greetings Leeblackman! Other than weighting, it is important to properly rinse / clean your BC as well as other gear. Regulators can be harmed if not properly rinsed after salt water exposure. It is not a big deal just a little time and care to ensure gear is rinsed in fresh water. Do not forget to flush your bladder in your BC! I returned from Mexico and dove the next week end in Gilboa. When I flushed my BC bladder my inflator tasted salty! It took several fresh flushes to get the salt out.
Different kinds of fish and plants but wet is wet both are equally awesome!
Diving is to great to not enjoy every week end, thus local waters are easier to get to.
I chose early in my diving to not limit myself to only vacation diving and found local diving to be equally exciting!
Have fun and safe diving to you my friend, there is always a new frontier to discover!
CamG Keep diving....keep training....keep learning!
 
Greetings Leeblackman! Other than weighting, it is important to properly rinse / clean your BC as well as other gear. Regulators can be harmed if not properly rinsed after salt water exposure. It is not a big deal just a little time and care to ensure gear is rinsed in fresh water. Do not forget to flush your bladder in your BC! I returned from Mexico and dove the next week end in Gilboa. When I flushed my BC bladder my inflator tasted salty! It took several fresh flushes to get the salt out.
Different kinds of fish and plants but wet is wet both are equally awesome!
Diving is to great to not enjoy every week end, thus local waters are easier to get to.
I chose early in my diving to not limit myself to only vacation diving and found local diving to be equally exciting!
Have fun and safe diving to you my friend, there is always a new frontier to discover!
CamG
Keep diving....keep training....keep learning!

Excellent points Cam. Another thing to bring up with the whole saltwater diving/rinsing gear is the order in which gear is rinsed. I always take care of my own gear, no matter where and whom I am diving with. Most dive operators should have a policy of regs/BCs first, then all other equipment. If you have people putting in booties, fins, gloves, wetsuits, etc first or at any time before all the regs/BCs are rinsed, it really opens up divers to myriad potential health issues, not to mention the possibility of having a reg that tastes like foot when you go to take a breath the next day.
 
Your weight requirement as you said will change.

The depth will be off but it is a small error. It really does not matter because your depth gauge really measures water pressure and the pressure (not the distance from the surface) is what drives you tables or computer algorithm.

In stormy times a small body of fresh water may be perfectly enjoyable while the ocean is all riled up.

One quip is that ocean diving is about what you can see and fresh water is about what you can find. In general fresh water has a lot of history on the bottom. Bottles, artifacts and old structures tend to be easier to find in fresh water, at least a round here.

Your gear is more apt to pick up a bio load in freshwater and stink afterward.

Freshwater due to it being generally less agitated will stratify and develop thermoclines. This can result in tropical warmth in the top 15-25 feet and frigid temperatures below. The ocean tends to be more mixed with temperatures changing as you move away from shore.

Fresh will get comfortably warmer earlier in the season but cools down below the ocean temperature in mid autumn.

In general we dive the fresh water sites to escape heavy seas, tease ourselves in warm water or enjoy a wet suited dive latter in the season. It also makes a nice change of pace.

Ice diving is not as likely in salt water.

Pete
 
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I understand that one typically needs more weight when diving salt water vs fresh water. What are some other issues that occur between the two? Are there issues in reading depth?

The difference in water density is not going to make a noticeable difference in your depth reading.

One atmosphere of pressure occurs in approximately 33 feet of sea water.
One atmosphere of pressure occurs in approximately 34 feet of fresh water.

Another way of looking at it is that at 99 feet in the ocean the water will exert a pressure of 3 atmospheres.

In fresh water the water would exert 3 atmospheres of pressure at 102 feet.
In other words, if your dive computer is calibrated for sea water your dive computer would theoretically read 99 feet on a fresh water dive that is actually at 102 feet.

In reality no dive plan should be cutting plan so close that 3 feet of depth makes a noticeable difference.

I am purposely ignoring the one atmosphere of pressure that exists at sea level for the purposes of this example.

When you are at 99 feet in the ocean you are actually at 4 atmospheres of pressure. Three atmospheres of pressure are due to the water pressure and the other atmosphere of pressure is from the one atmosphere of pressure that exists at sea level (14.7 PSI).

Hopefully this answers your question without making things more confusing.
 
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