The Great "Salt in Non-SWG Pools" Experiment

[NWMNMom]

Last year a number of PF users decided to try something different. One after another, a limited group of users became our own guinea pigs to determine if there was any benefit to adding/increasing salinity in our pools, without the use of a SWG. From what I recall, the group consisted of AG pool owners, but I will double check my facts soon and update as needed. The entire idea was born out of complaints regarding chlorinated water, eyes, hair and skin.

I am not great at calculations but it seems to me that, with our pool size and 120# of solar salt, we got numbers somewhere around 700ppm. The water felt SO nice. My kids could swim with their eyes open, our hair and skin were softer after swimming. These are my observations and opinions, not scientifically based or proven facts, but I wasn't alone in those observations.

There was great concern about some posters regarding damage the salt may cause to equipment and materials. There were discussions and pondering sessions regarding freezing points. There were notations about bouyancy. The thread was active and continued so that it became HUGE. Would anyone who participated in the experiment care to add any facts or specifics for the courious? Maybe we can condense our findings so we don't repeat the size of the thread at PF (makes it hard for someone to know whats what without reading PAGES and PAGES)

 

[mbar]

I am very interested in this too, so I am replying to put it back at the top. I plan on adding salt this year to my inground fiberglass pool which holds about 16,000 gal.

 

[medvampire]

I salted my pool last year and the family has loved it. The water feel has become less harsh with more of silkiness. The most important thing for me was eye and nose irritation. With the salt you can open your eyes under water with a reduction in the dreaded red eye look. I have also noted less nasal burn when you get water up the nose.
The salt doesn't soften the water but changes the osmotic pressure. Osmosis is movements of fluids from a less concreted solution to higher concretion in regards to the solvent. In our case it is a movement of water from the pool in to the tissues of our body. Our bodies are 9000 ppm salt so the closer we get the salt concretion in the pool to that of the body the less osmotic pressure will be exhibited on the skin. Just for contrast the ocean is around 35000 ppm and the Dead Sea is around 300000 ppm. Most SCG run salinity around 3000 ppm. I run my pool last year around 2200 but haven't tested or adjusted my salinity this year yet. I checked with my pool manufacture and they would have no problem with warranty at the levels for a SCG.
I have noted that leaves and such tend to dissolve a little more slowly but haven't noted a change in the pool ability to prevent algae or bacteria growth.
I would give this a big thumbs up but remember the only way to totally reverse this is drain and refill.
Steve

 

[SeanB]

I have noted that leaves and such tend to dissolve a little more slowly but haven’t noted a change in the pool ability to prevent algae or bacteria growth.
Steve

That would be a good thing too, since you will have fewer dissolved organic compounds in the pool. Salt is all we have ever had so I didn't realize that the leaves might be breaking down more slowly. Of course, I try to get them out ASAP anyway.

 

[The Mermaid Queen]

I'm interested in the corrosive effects of lower (non-swcg) salt levels on an AGP... Steve and NWMWMom, or others who 'experimented', did you notice any negative effects?

 

[NWMNMom]

I did not notice any differences anywhere. I don't really have any metal IN the pool that isn't covered by the liner, the rails show no corrossion, the tools/equipment we used to clean the pool as well as the pumps, etc., showed no issues. The liner was just fine. My opinion is that there were no noticable issues there.

I purchased additional salt yesterday as we are topping off the pool tonight (drain below skimmer last fall depleted some salt) I agree with MedVampire that it just feels wonderful in that water vs. the non salted.

 

[sevver]

I put salt in my pool last year, and I noticed the water was not a drying on the skin, and when it moved, it just looked silkier. This could totally be my own imagination.

But, I have psoriasis, and last summer it went away seemingly after I added the salt. And interestingly enough, it is back now. Even more interesting is that people go to the Dead Sea to relieve it, and alot of study seems to be being put into the effects of Ultra Violet rays and Salt Water on it.

As for corrosion, I doubt that the effects would be noticeable at such a low ppm, I have not noticed anything.

 

[NWMNMom]

That too....

I agree on the psoriasis thing. My DH has very bad psoriasis and sun always helps some, but the salt in the pool did make a difference - especially on the scalp, which he doesn't expose to sunlight much so no help for him there (wears one of those darn hats all the time at home, hard hat at work)

I just think that its closer to the salinity of our body fluids so has less adverse effect than just chlorinated water, which is harsh. We love it and will continue until someone tells us its the wrong thing to do and can prove it.

 

[medvampire]

One thing to remember is that the main oxidizer in salt is the chlorine. I don't see where salt it's self would be any more corrosive than the chlorine we use in the pool.
Steve

 

[chem geek]

The main issues with corrosion of metal in salt pools (independent of whether an SWG is used) has to do with two effects:

1) High levels of chlorides (especially in the presence of sulfates) prevent the passivity layer from forming on stainless steel so while the chlorine is indeed the oxidizer that corrodes the "steel" (iron) of stainless steel, the chlorides interfere with the self-healing process of stainless steel.

2) The higher level of salt in the pool increases the conductivity of the water and that increases corrosion from electrolytic (if sufficient voltages are present) or galvanic (dissimilar metals electrically connected) processes.

Though these two statements are technically correct, they do not indicate the rate of such corrosion at what specific levels of chloride or conductivity, etc. We know that 3-5 ppm Free Chlorine with no CYA in a salt pool will corrode stainless steel very quickly -- in less than a year -- as there were multiple reports (and a study) of that kind of corrosion on the Pool Forum. Details about this and references to EPA documents are at this thread on the Pool Forum.

I would say that having CYA in a pool makes the disinfecting chlorine level low enough to not cause problems with typical metal corrosion including stainless steel. However, dripping salt water outside the pool onto metal (steel) has had a few reports of corrosion which makes sense given the concentration of salt after evaporation. It should be remembered that a non-salt pool still has salt in it. After initial startup of a pool, there is about 350 ppm chloride (as ppm sodium chloride) and after using chlorine it is not uncommon to find 500-1000 ppm salt, especially if liquid chlorine (bleach or chlorinating liquid) is used.

 

[NWMNMom]

Uh, what he said. OK. I agree, and its a good heads up for anyone who puts salt in the pool and who doesn't have CYA in the pool. (umm, most of us do have CYA excepting those that don't follow the BBB methods....) I'm guessing more often than not, some will have more CYA than recommended due to using pucks and tabs, etc.

Much thanks to all of you who are able to provide the technical info on these matters. I feel comfortable providing the "it feels great, makes my hair and skin feel great" side of the equations...lol

 

[Lisa]

Just out of curiosity, how do you measure the salt ppm in your water? Are you using the salt that is used for water softeners? How much do you add? This sounds great ... I'd like to give it a try this year!

 

[medvampire]

You can test salt at home but just for this I run a sample to the pool store and get them to test. When they finish testing for salt and other I listen and nod my head and walk out of the store. I might get some test reagent this year but who knows. After you get an starting point for your salt grab this Bleac Calc. Decide where you want your salt level to be and plug in the numbers in Bleach Calc and get the needed amount of salt. Time to buy salt I put

in my pool.
Main thing to remember it needs to be as pure as possable.
Drop the salt in the pool I just dropped mine in the center with the pump running and kids splashing and it was dissolved in a few minutes. I took a sample in the store a week later and found I had overshot my goal of 2000 by 2200. I wasn't worried due to SCG run around 3000
Steve

 

[NWMNMom]

Hey Steve, thats the same brand I am using! Just bought a supply a couple of days ago.

 

[gonefishin]

That's the same brand I've used in my above ground pool too. I noticed that in many other brands they contained additives to fight iron and rust stains. The solar salt crystals also dissolved easily when dumped just in front of my discharge return. I just dumped the salt in and then aimed the return right on the salt pile.

dan

 

[NWMNMom]

Yep, it dissolves quite nicely and quickly. That is a good reminder, do NOT buy the salt with rust inhibitor, conditioners or other additives. Just look for one that says 99.something pure and thats all. Also, not ROCK salt, not pure and I thik most of the pellets actually have additives too. Solar salt seems to be a very safe bet and usually pretty darn cheap too - Mine was on sale for $2.49 per 40# bag. Can't beat that with a stick!

 

[Rangeball]

I did this last year as well. Never had an initial salt test, my best estimate is I went to 1200 pm. Used the same blue bag of solar salt posted above.

Water felt much better, hair and skin much softer after getting out, less eye burning. I have a 21,200 gal IG pool and have not noticed any corrosion or ill effects from the salt.

By the way, nice place you got here. I recognize some of you from PF.

 

[55k]

Bump for any follow up

 

[AnnaK]

I'm glad to see this thread make it around again.

We were one of the AGPOs (above ground pool owners) who added solar salt, 120# to 12,000 gallons. It made an amazing difference to the water feel, very soft and silky. No more red eyes and much less 'cloudy' eyes when swimming with my eyes open under water. Nice soft skin and hair when we got out and far easier on the dogs' coats.

We could probably have added more salt but we liked the way the water felt at 1200 ppm and stopped there. During winter the pool froze as it always had, a block of ice by January and thawed by mid-April.

 

[seadogg]

I just did it this year and the family loves it; see this recent post. I don't have my salt water test-strips yet; but expect it's about 2,000 ppm.