Salt Level For Chlorine Generator..

[kaplan]

I just drained my pool to fix the large wrinkles in the vinyl liner last week. I filled the pool up and am getting the pool ready to conver it back to salt. I used the poolcalculator to estimate the amount of salt for my 30,000 gallon pool. It appears that I haved added too much. My test strips consistantly show 3,800-4,000ppm. My question is at what level is the salt too high and needs to be lowered. Is it bad in long run if your salt levels remain over 4,000. Should I backwash some water out and adjust it to 3,000 or will it be fine. I have an autoclear plus polaris unit. The manual states 3000-3500 for ideal salt concentration

Thanks in advance for any help

[waterbear]

I don't believe the Polaris units have a high salt shutoff so you should be fine. If your salt is not above 4000 ppm ppm you should be fine. You can backwash a bit more frequently but you will need to raise the CYA once you lower the salt. Polaris recommends a salt level of 3250 and and a CYA of 80 ppm for the unit for best performance.

[kaplan]

I drained some of the water and refilled..now at 3700. Thanks waterbear for the response

[AquaclearNZ]

I drained some of the water and refilled..now at 3700. Thanks waterbear for the response

The concentration of salt at that level will not hurt your other equipment - in New Zealand and the southern hemisphere we have high salt chlorinator models that like up to 7ppm salt

[chem geek]

The concentration of salt at that level will not hurt your other equipment - in New Zealand and the southern hemisphere we have high salt chlorinator models that like up to 7ppm salt

And you also don't have soft limestone hardscapes, diving boards with steel mounts, aluminum headers in automatic pool covers, or thin copper heat exchangers in gas heaters. Salt levels do matter with respect to corrosion. It's not a problem for most pools, but you can't say it isn't a problem for all pools -- one needs to be at least a little careful. An extreme blog about such problems is here. The problems that are mentioned can generally be mitigated (sealing soft hardscapes or using less absorbent stones or washing regularly; using cupro-nickel or titanium heat exchangers; adding a sacrificial anode to the bonding wire).

Richard

[Strannik]

I don't believe the Polaris units have a high salt shutoff so you should be fine.

that's actually a bad thing

instead of shutting off, it will just burn the transformer

but that will happen somewhere around 6-8000ppm, 4000 shouldn't be a problem

[waterbear]

I don't believe the Polaris units have a high salt shutoff so you should be fine.

that's actually a bad thing

instead of shutting off, it will just burn the transformer

but that will happen somewhere around 6-8000ppm, 4000 shouldn't be a problem

Like I said, Fine!

[Swimming Pool Experts]

I just drained my pool to fix the large wrinkles in the vinyl liner last week. I filled the pool up and am getting the pool ready to conver it back to salt. I used the poolcalculator to estimate the amount of salt for my 30,000 gallon pool. It appears that I haved added too much. My test strips consistantly show 3,800-4,000ppm. My question is at what level is the salt too high and needs to be lowered. Is it bad in long run if your salt levels remain over 4,000. Should I backwash some water out and adjust it to 3,000 or will it be fine. I have an autoclear plus polaris unit. The manual states 3000-3500 for ideal salt concentration

Thanks in advance for any help

The ideal mix ratio for all brands of chorine generators is 25 lbs. of salt per 1,000 gallons of fresh water for new pool water. Many brands of chlorine generators will only operate within the specifed ranges, although some like the AutoPilot will operate and produce chlorine even as high as 35,000 ppm. You may need to discharge some of the pool water and replenish with some fresh to dilute and lower your salt concentration. If your unit is equipped with a high salt low salt indicator light, just check it to see if this is needed. Also, you can see if the "Generating" light is on, which indicates the unit is producing chlorine. If it is, then no dilution is needed. Over a short period of time the salt level will begin to reducs as chroine is produced.

Fact: elevated chlorine levels in a pool are more harmful to pool components than the recommended salt level concentrations in pool water. So, don't let anyone tell you that salt water (at the levels we use to produce chlorine in pools and spas) is harmful to your equipment. That is just not true, chlorine is worse.

[chem geek]

Fact: elevated chlorine levels in a pool are more harmful to pool components than the recommended salt level concentrations in pool water. So, don't let anyone tell you that salt water (at the levels we use to produce chlorine in pools and spas) is harmful to your equipment. That is just not true, chlorine is worse.

It is true that chlorine is a strong oxidizer and harmful to weak metals which is why regular steel and zinc are not used in pools. Nevertheless, it is not true that higher salt levels are not more corrosive. The 2-6 times higher conductivity increases metal corrosion rates. Also, stainless steel, aluminum, and possibly copper are all affected by increased chloride levels which interfere with the formation of passivity layers (see this link especially p. 28 and note that with chlorine, it takes less salt to have the same effects). The worst effects that are seen are with the following:

1) Aluminum header bars in automatic "vanishing" pool covers that have such headers touching (immersed in) the water.

2) Aluminum rails at the sides of pools for some types of automatic covers when water splashes out and evaporation concentrates the salt (see this post and ones that follow it).

3) Steel bases of diving boards and some patio furniture when water from swimsuits drips and evaporation concentrates the salt.

4) Porous hardscape materials (natural stones) especially certain limestone that are susceptible to splash-out and evaporation concentrating salt with recrystallization pressure.

5) Copper heat exchangers -- maybe.

6) Stainless steel in pools with no CYA (such as most indoor pools) -- see this link though not all IP addresses can access it.

7) Some metal components in pool cleaners and other equipment -- maybe.

All of the above happens anyway in any chlorinated pool, but the increased salt levels can make these things happen more quickly. As to whether this is a problem or not depends on the strength of the materials since going from 30 year to 10 year corrosion may not matter if the material degrades in 10 years from other factors not related to salt or chlorine levels. On the other hand, accelerating corrosion from 5 years to 2 can be more serious. The argument that the salt isn't the primary cause and it's the chlorine is really a moot point since you've got to have the chlorine anyway so the salt is the item that can put things over the edge (except for the "no CYA" cases).

Most people don't have problems with their SWG pools, but some do, so it is irresponsible to claim that there are no problems with the increased salt levels. All of the aforementioned issues can be mitigated, such as using sacrificial zinc or magnesium (for aluminum) anodes or sealing stone or use of cupro-nickel or titanium heat exchangers or using CYA. People should be informed of the risks and when they apply.

Richard

[Strannik]

The ideal mix ratio for all brands of chorine generators is 25 lbs. of salt per 1,000 gallons of fresh water for new pool water.

That's not true. A lot of chlorine generators have 4500 as a minimum, which is much higher than 3000ppm you are recommending.

[waterbear]

Gotta love it when someone with 1 post under their belt and the name "swimming pool experts" isn't.

Strannik, you beat me to the same answer.

I guess this person has never seen a Zodiac, Poolex, Resiliance, or the vast majority of SWGs on the market. The ones that use a salt level of 3000-3200 are actually in the minority!

[AquaclearNZ]

the increased deterioration caused by salt is not going to vary a lot between 3pt and 6pt salt

the simple fact of having salt present i nthe pool water and a form of electrolysis going on cuts the life of most of the equipment by 50%

we do have soft stone finishes, and i wouldnt recommend using salt at any percentage around them

ladders and diving boards - we have those too ,the difference in the speed of degredation to this equipment would be negilible, you have already cut its life in half by adding salt to the pool

and the original concern was adding slightly higher salt than the manufacturers recommendation around the 4ppm mark........... if the original concern was the salt level was at 40ppm or similar, then my answer would have been somewhat different

[chem geek]

You are right that I am mostly talking about the differences between non-SWG pools with 500-1000 or usually less than 1500 ppm salt vs. 3000+ ppm for SWG pools. There are non-linear effects with regard to stainless steel corrosion at 5000 ppm, but those were mostly seen when chlorine was used with no CYA (and one user had 3-5 ppm FC with no CYA with stainless steel corrosion within a year after converting an indoor pool to SWG with 3000 ppm salt). I was mostly commenting on your statement: "The concentration of salt at that level will not hurt your other equipment - in New Zealand and the southern hemisphere we have high salt chlorinator models that like up to 7ppm salt."

As described in this thread, sometimes the problem is the use of inferior materials as with some above-ground pools where the salt just accelerates a corrosion problem that would have likely occurred over a longer time anyway. This post shows the effects of splashed-out salt on an aluminum automatic cover track for an indoor pool. With 3-6 times the amount of salt in a typical SWG pool compared to non-SWG pool, there will be 3-6 times as much salt splashed-out.

When I asked my pool builder if he saw any differences in the SWG pools he now services (he says 85% of his new installations are SWG pools), the main problem was with aluminum header bars for "vanishing" automatic pool covers where the bar is immersed in the water. The use of a sacrificial anode (presumably magnesium) has resolved this problem.

Richard