Saltwater v Auto Chlorine Regulator

[Simon]

I've "ummed" and "ahed" over which system to use in the pool we are about to have built.  I know Poolguy recommends an auto Chlorine/pH regulator, but I woujld be interested to hear from people who have either system on the pros and cons - especially if you have changed from one to the other.

The summary I have currently in my head is:

1) Auto Chlorine/Ph - very easy, low maintenance (but more chemicals to mess with in the pump-room), more hygenic, potentially higher "irritation" on skin - less expensive box of tricks

2) Saltwater - not so low maintenance (but do not know why), better feel on skin - more expensive box of tricks.

Any help more than gratefully received.

Rgds

Simon

   

[JJ]

Simon,

I have been running a salt water system for 4 years now. I liked the sound of it and thought it would be more friendly all around.

There are lots of pool owners out there who have salt water systems which run very well, alas, mine seem to be a permanent challenge.

Salt water systems are not automatic, I am always testing various levels. You need to be a chemist to be on top of it.

There are no less chemicals in my pool house than any other, hydrochloric acid, eua de javel (choc), cyanuric acid, bicarb of soda for example.

And salt, yes the salt, I have put in 16 x 25kg bags this season, some of that might be due to winterising wher I dropped the level. That is a lot of salt, itr is heavy and bulky, and at between 6 to 12 euros a bag, not exactly cheap.

And as to the enviroment, that is another issue, apparently one is not allowed to discharge salt water into the water table, which makes for some problems.

When it is running well it is fine, but I would not recomend my salt water system to a potential pool owner.

I will be changing to a direct injection liquid chlorine system when I can afford it.

Hope this helps.

 

 

[oliveau]

I put in a salt water system with a new pool [10m x 5m x 1.8max] 2 years ago. It took 8 bags of salt at installation and a further 8 when the pool company recommissioined last spring. [I think they wanted the sales at 16 euros/bag!]

I had an abri fitted last July and since then I hardly need clean the pool or filter, and we were swimming at 21C by Easter without any heating having been used.

I put the pool back in service myself - 2 x 30 minutes of vacuuming to waste, a touch of pH minus, and no salt or choc needed. When I do need salt I shall use ordinary water softener salt from Bricomarché.

I have a 'Monarch' chlorinator [cost about 2000 euros] which chlorinates as required and it will indicate if the salt needs topping up. I run everything for 9 hrs/day in the summer, and 30 mins/day in the winter.

It's dead simple folks - I just get on and enjoy the pool!

Bon courage, Peter

 

 

 

[Poolguy]

I thought I would let this run a little before responding.

Most of the regular visitors to this section would know my views anyway.

But for the new commers it would be important to get the facts straight. So I'll make up a detailed response and post it in due course.. that is if there is any interest.

Lot of people say that they read these threads but not many contributors which is sad.

Andrew

 

[YCCMB]

OK I'll bite............can somebody explain, please, that each time this debate is raised, there's this business of how much salt is put into the pool, followed by statements about discharging salt water into the drainage system......and yet, there's also every time the statement about salt water pools converting the salt to chlorine "just like a chlorine pool". So which is it to be? Is the pool water in a salt water chlorination system chlorinated water or salt water?? Because if the salt is converted into chlorine (which I understand it is), then the water in the pool ends up being chlorinated water, not salt water, and thus, unless you're emptying your pool just after you've tossed in bags of salt, there's essentially no difference between the two. Or is there? Just curious. Incidentally, I'm under no illusions here. I know, and always have known, that a salt water pool converts the salt to chlorine (or words to that effect) so we can just cut to the chase on that aspect.

[Poolguy]

Thanks for the question Betty (nice pic)

Basically, once water is salinated then it will always be salinated, (unless of

course you can distil it)

The idea of putting salt (sodium chloride [NaCl] http://hyperphysics.phy-astr.gsu.edu/hbase/molecule/nacl.html)

into the pool is to provide the base raw material for the electrolyser to

section out Chlorine from the salt.

But to do this you need an awful lot of salt (3-6000ppm) in order to get a paltry

1-3ppm of chlorine maintained in your pool- the consumption of salt from this

process varies from pool to pool but it would amount to 100-200kg per year. But

in no way does this water ever return to fresh or just 'chlorinated'... 

it is the chlorine which is consumed sanatising the water and by ultra violet

light, the salt just stays ther floating around mush as it does in the sea.

The reason that we are talking about the environmental impact of salinating this

water is very topical as Globally, fresh water stocks are dwindling and so

technologies which can sanitize without polluting the water with salt are

coming into favour in exemplar countries - regrettably France is not one of

them as the use of salt is widespread.

So, concern for the environment notwithstanding, there are many other practical

reasons why running a salt pool is not so advantageous, but I would prefer to

leave that rest a little to see what other concerns are raised.

Andrew

[YCCMB]

Ah, thanks, now I'm clearer. I was always mediocre at chemistry! We get away with quite a bit less salt than 1-200Kgpa, though. About half that, usually, in an 8 x 4m pool. But at least now I understand!

[Graham & Brenda]

Just to contribute my 2 pennyworth. Our salt pool is coming up to 3 years old and it couldn't be easier to run. After testing I did not add salt this spring, just some ph+. We have a bidon of liquid ph- conected for auto - adjustment but I turn it off for half an hour or so after cleaning the filter or it can get confused into adding ph- when it is not needed. Other than cleaning the filter and adding ph+ if indicated on the doofer that's it. Lovely clean, odour free water.

[Simon]

Thanks to all for your responses.

After much soul-searching (and changing my mind several times) I have decided to go with the Auto Clor/Ph solution.  I'll let you know how I get on!

Simon

[chirpy]

If we have   a salt water pool and all  the salt is converted to chlorine then we have sodium hydroxide left dissolved in water-therefore discharge of any water is going to be slighly alkaine solution of sodium hydroxide when all chlorine used up.

I DO NOT SEE WHERE  ANY  SALT IS BEING DISCHARGED INTO THE SOIL .!???

15ALL I THINK AS WE APPROACH THE TENNIS SEASON>[:)][8-)][;-)]

[Cat]

I'm no expert, but I don't think the salt is converted to chlorine, it just acts as an agent in the electrolysing process to create chlorine.  So when the filter is back-washed, the salt is discharged into the soil.

I expect Poolguy will come up with a definitive answer.

 

[chirpy]

SORRY BUT SALT IS CONVERTED TO CHLORINE AND THE SODIUM IN THE SALT TO AN ALKALI CALLED SODIUM HYDROXIDE.THIS IS ELEMENTARY CHEMISTRY.

[Jonzjob]

I am sure that Andrew can correct if wrong, but I am under the impression that not all the salt is converted and that is why the problem of salt discharge is there.

I have an auto chlor system and apart from a couple of problems with the auto valves I have clear water that does not smell of anything but water? Also, what is the difference between a chlor pool and a salt/chlor pool if your salt pool has 3 ppm chlor in it anyway. My chlor pool has 3 ppm in the water when it's running correctly, which it does. It is suggested that I will come out of my pool smelling of chlor and the person in the salt pool won't. I don't smell of chlor! The only differences I can see is that my pool is checked for chlor and PH every 3 minutes and adjusted automatically and a salt pool has salt in it as well.

I know that if I swim in the sea I need a shower when I come out because I feel sticky from the salt. I don't need anything other that a towel when I get out of our pool.

Something else on a slight tack. With a abri someone has already said that they have been in the pool at 21 degC this Easter. When the sun gets more powerful and the water really starts to get warm how do you stop it getting too warm. Someone, last year I think, was saying that their pool got so warm that they had to open the abri so as not to over heat it? They left it open even when they went out. This would have contravined the conformaty would it not (sorry about the spelling?) ?

I'll stick at getting a 20 litre bottle of chlor about every 6 to 8 weeks through the summer. At about 12€ a go it ain't dear.....

[oliveau]

You open it up for your afternoon swim - usually does the trick!

Peter

[Poolguy]

[quote user="Poolguy"]Thanks for the question Betty (nice pic)

Basically, once water is salinated then it will always be salinated, (unless of course you can distil it)

The idea of putting salt (sodium chloride [NaCl] http://hyperphysics.phy-astr.gsu.edu/hbase/molecule/nacl.html) into the pool is to provide the base raw material for the electrolyser to section out Chlorine from the salt.

But to do this you need an awful lot of salt (3-6000ppm) in order to get a paltry 1-3ppm of chlorine maintained in your pool- the consumption of salt from this process varies from pool to pool but it would amount to 100-200kg per year. But in no way does this water ever return to fresh or just 'chlorinated'...  it is the chlorine which is consumed sanatising the water and by ultra violet light, the salt just stays ther floating around mush as it does in the sea.

The reason that we are talking about the environmental impact of salinating this water is very topical as Globally, fresh water stocks are dwindling and so technologies which can sanitize without polluting the water with salt are coming into favour in exemplar countries - regrettably France is not one of them as the use of salt is widespread.

So, concern for the environment notwithstanding, there are many other practical reasons why running a salt pool is not so advantageous, but I would prefer to leave that rest a little to see what other concerns are raised.

Andrew


[/quote]

I believe that I have answered most of questions in my previous posts.

Thanks to Jonzjob and Cat for your contributions.

But to clarify not just for AB's benefit and those others who might be confused by this thread which is getting unnecessaily technical when it comes to the choice between the systems. I reiterate.

When you fill your pool for the first time the water is fresh, the salt content is about 50-200ppm typically in France. People who hav bought a Electrolysis system are then obliged to dose the pool with about 5-8 kg of pure salt (sodium chloride) per meter3 to bring the level to 3000-6000ppm, about 1/10 that of the sea, thats about 300kgs for the average pool . The Electolysis machine then extracts Chlorine in gaseous and liquid form from the Sodium chloride but it is by no means a complete conversion as the power generated by throught the plates is too feeble to do much more than 10-20 mlg of chlorine per hour. Also produced are ozone gas, hydrogen gas, about 8 different salts of various makeups, and calcium deposits come out of solution. The chemistry to my mind is by no means elementary and by no means simple. The work we do with some of the top acedemics in the world bears out that this is important science- and not a doddle. It also means that the water is still salty and will ever after always be so - consequently you are obliged to gard against introducing your contaminated salty water into the fresh water environment. Its the law in Europe now.

In other countries, the problem of water shortage is so cronic that it is impacting on the pool industry with dramatic consequences. It is Law in NSW that any pool over 50m3 must collect rainwater from the roof for pool topups; the pool must be fitted with antievaporation cover; and the house must have water conservation measures. Secondly the price for salinators will now rise 40% for reverse polartiy and 20% for standard, making them far more expensive than the superior technology and benefits offered by direct injection.This is not yet in France but that day is approaching I suspect.

Andrew