Totally New to and Curious about Chlorine Generators

caliskier

LifeTime Supporter
Aug 24, 2014
329
Oklahoma City, OK
Hi,

I am simi-clueless on Chlorine Generators and am considering switching when I replace the liner soon... I reviewed pool school and some other sites please help me clear up a few things...

1. Are chlorine generators and saltwater chlorine generators (SWG) the same thing? Or let me ask it this way... Are there 3 types of sanitation? Salt Water pools, Manually Chlorinated Pools, and Chlorine Generated Pools?
2. If I get a chlorine generator does that make it a saltwater pool?

If chlorine generated is different from SWG, I would prefer chlorine generated, so the rest of the questions should be answered from that perspective.

3. Do they pay for themselves in say 5 - 7 years?
4. How long do you have to run the pump on a 20,600 gallon pool?
5. How much liquid chlorine will I need to buy in a season if I am currently buying 100 gallons?
6. I read that it costs about $50 a season to run just the generator, is that about right?
7. I assume my delta costs will be, generator run time, extra pump run time to chlorinate, liquid chlorine supplements, anything I am missing?
8. Do I need to test the water and/or add chlorine every night still when I have one?
9. If it is really saltwater, will it be hard on my 30 year old equipment? (liner pool. worried about the steel walls)
10. Are they hard on liner pools?
11. Is it better to spend a little extra to buy a 40,000 gallon or 60,000 gallon generator so I can run the pump less? Today I only run my pump 4 hours a day.

Thanks for the help, what I have gathered on my own from commercial sites (but would like your experience) is that they do pay for themselves eventually, are not typically hard on pools for SWG, but jury is still out. Question 1 answer might clear a lot up for me...
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
23,517
Laughlin, NV
There are only Salt Water Chlorine Generators. The other way to put chlorine in your pool is liquid chlorine or solid chlorine (not recommended).

The up front cost of a SWCG is roughly equal to the use of the other forms of chlorine. Most SWCG's will last ~10000 generating hours.

A 40K rated SWCG would need to run ~12 hours per day in the heat of the summer. A 60K rated would need to run about 8 hours.
Your issue is your single speed pump. It costs many times more to run than a variable speed. So if you wish to use a SWCG, it might be something to consider to change to a VS pump.

You would only need to buy/use liquid chlorine when the pool water is too cold for the SWCG (below ~60F) and if you let things go and have to SLAM Process.

You need to test enough to be sure your FC stays above minimum. Normally that means you can test every day or two. You do need to monitor pH and add acid as necessary as pH will tend to rise as you are no longer using acidic trichlor.

The salinity in a SWCG pool is just a little more than a pool chlorinated with liquid or solid chlorine. They both add salt to the water. The saltwater is not hard on equipment or your pool. High or low pH is far more destructive and must be managed.

Hope that helps.
 

caliskier

LifeTime Supporter
Aug 24, 2014
329
Oklahoma City, OK
There are only Salt Water Chlorine Generators. The other way to put chlorine in your pool is liquid chlorine or solid chlorine (not recommended).

The up front cost of a SWCG is roughly equal to the use of the other forms of chlorine. Most SWCG's will last ~10000 generating hours.

A 40K rated SWCG would need to run ~12 hours per day in the heat of the summer. A 60K rated would need to run about 8 hours.
Your issue is your single speed pump. It costs many times more to run than a variable speed. So if you wish to use a SWCG, it might be something to consider to change to a VS pump.

You would only need to buy/use liquid chlorine when the pool water is too cold for the SWCG (below ~60F) and if you let things go and have to SLAM Process.

You need to test enough to be sure your FC stays above minimum. Normally that means you can test every day or two. You do need to monitor pH and add acid as necessary as pH will tend to rise as you are no longer using acidic trichlor.

The salinity in a SWCG pool is just a little more than a pool chlorinated with liquid or solid chlorine. They both add salt to the water. The saltwater is not hard on equipment or your pool. High or low pH is far more destructive and must be managed.

Hope that helps.
This helps a lot, thanks!!!

the 40k vs 60k - 12 vs. 8 hrs, is that for my pool size?
I need to research pumps now that you said that.
When water is below 60 I close it and winterize it.
 

tomfrh

Well-known member
Jan 30, 2018
410
Australia
There are big chemical factories which produce chlorine. You can buy this chlorine in liquid or solid form and tip into your pool each day.

An SWG, aka chlorine generator is a miniature chlorine factory attached to your pool which does much the same thing, so you don’t have to keep going to the shop to buy chlorine. You feed it salt, hence these pools being called salt water pools.
 

Chuckiechan

Well-known member
Jun 10, 2014
448
Roseville, CA
An SWG does require you to pay closer attention to chemical balance. During operation, they tend to push Ph up. And that can lead to a clogged cell depending on the chemical and mineral balance in your pool. To combat that you have to stay on top of Ph and keep it around 7.5 - 7.6, depending. That is one reason why many borate their pools since borates help keep the Ph from making rapid swings (AKA buffering) and causing trouble . In my pool it "parks" around 7.6 without me adding a lot of acid.

I say go for it. Scheleping pool chlorine is a pain, acid is a pain too, but you use less of it when you are running in the sweet spot.

BTW, I have a Circupool generator, while inexpensive ($630) lasts for about three years. They say they run for 10,000 hours which in my case is hogwash. For a new comer, I'd recommend paying more and going with a Hayward or other top brand as they seem to be more forgiving. In the SWG specs, look at what S.I. they recommend and run it buy the experts here. Mine is - 0.02 to + 0.02 which IMO is pretty tight.

Lastly, I have a plaster pool so some of my worries may not apply to yours.
 

tomfrh

Well-known member
Jan 30, 2018
410
Australia
I just want to clarify - you do not 'feed' the SWCG salt. A SWCG does not 'consume' salt.
Yea theoretically it gets recycled. But in practical terms it runs on salt and so you have to add a lot of salt at the start, and keep adding salt from time to time as the salt is lost for one reason or another. Like fertilising your garden.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
4,758
Central California
Some conflicting info here.

caliskier, the primary source of your confusion is that there are about 200 different names and acronyms for these machines. They are all the same thing, it's not just you!! ;)

You can add salt to a pool to make the water feel "silkier." No SWG required. Some people do just that. Salt accumulates in a non-swg pool, because chlorine and acid and people leave salt behind. But you have to have/add salt in order to use an SWG, and the amount of salt must be within a certain range (depending on brand). An SWG doesn't make your pool a saltwater pool on its own.

Salt does not get used up by the SWG. Nor does it evaporate. Salt is lost through splash out (kids playing, etc), cleaning certain types of filters, and overflow due to excessive rain. But it can get into your pool, too. Here where I live, my pool's salt level is steadily climbing and I don't expect to ever have to add salt. I'll be looking to get rid of it in a few years.

You can do all the math you want. Many before you have done just that. There are Excel spreadsheets around here somewhere that folks have worked on. But there are a lot of variables. The general consensus is that sanitizing your pool with an SWG costs about the same as doing do manually with store-bought chlorine. One you pay for up front, the other over time. One you have to haul and store a lot of chlorine, the other not so much. So they don't pay for themselves, they are a consumable, they wear out and you will buy another. For some, like me, they do "pay for themselves" in terms of convenience. So even if I did the math, allowing for pump runtime and electricity and blah, blah, blah, and it turned out that an SWG was costing me 10 or 20% more, I'd still use it. It's that convenient. I think you'll be hard pressed to find any other SWG users here that would claim otherwise. We all love them. So you can spend hours on cost analysis. Please share your findings if you do. Or you can just go get one and save the hassle. Either way, by this time next year you'll be one of us!! ;)

Now what will pay for itself, eventually, is a variable speed pump. That is something to seriously consider. Look for rebates, sell or repurpose the old pump. And then watch your electric bill drop. (Based on someone above saying you have a 1-speed pump.)

The use of an SWG will not significantly impact testing frequency. You get to know your pool, regardless of sanitation, and your testing regime finds its rhythm. You can't stop testing because of an SWG, if for no other reason than you have to make sure it's working and providing the correct level of chlorine.

What it can do, is free you up to leave your house for multiple days. With manual dosing, which in summer needs to happen most every day, you either have to stay home, coerce someone to add chlorine for you, or use pucks. All bad. With an SWG, that you have dialed in, you can risk sneaking off for a while and your pool will stay sanitized. It's not foolproof, but the possibility of freedom exists (that's the safest way to put it)!

Not often mentioned: SWGs do not work in water below about 50° (depending on brand). Which means at some point, for some number of months, you turn off the SWG and revert to treating your pool with chlorine manually. Typically the chlorine demand during those same months drops, so it's not as big a chore as swim season, but it is something to be aware of. Unless you'll be closing your pool for winter, you'll be supplementing your sanitizing system during off-season with liquid chlorine. You'll also sometimes need to goose your pool with liquid chlorine during swim season, like right before and/or after a big pool party. So SWGs do not completely eliminate the use of liquid chlorine in all pools.

An SWG does require you to pay closer attention to chemical balance. During operation, they tend to push Ph up. And that can lead to a clogged cell depending on the chemical and mineral balance in your pool. To combat that you have to stay on top of Ph and keep it around 7.5 - 7.6, depending. That is one reason why many borate their pools since borates help keep the Ph from making rapid swings (AKA buffering) and causing trouble . In my pool it "parks" around 7.6 without me adding a lot of acid.
Regarding that statement, if I may, that was pretty close, although there is no actual need to "pay closer attention." Same amount of testing and adjusting as non-swg pools, but maybe different kinds of adjusting is all. And it's more important to monitor and adjust CSI as needed, in the -0.3 to 0.0 range (which may or may not be done by adjusting pH). CSI is more of an indicator of how your cell will or won't get "clogged up" than pH is. I run my pH at 7.7 to 7.8 and my cell is fine because my CSI is in range. It's not accurate to say your pH will need to be 7.5 - 7.6. Every pool is different.
 

caliskier

LifeTime Supporter
Aug 24, 2014
329
Oklahoma City, OK
Some conflicting info here.

caliskier, the primary source of your confusion is that there are about 200 different names and acronyms for these machines. They are all the same thing, it's not just you!! ;)

You can add salt to a pool to make the water feel "silkier." No SWG required. Some people do just that. Salt accumulates in a non-swg pool, because chlorine and acid and people leave salt behind. But you have to have/add salt in order to use an SWG, and the amount of salt must be within a certain range (depending on brand). An SWG doesn't make your pool a saltwater pool on its own.

Salt does not get used up by the SWG. Nor does it evaporate. Salt is lost through splash out (kids playing, etc), cleaning certain types of filters, and overflow due to excessive rain. But it can get into your pool, too. Here where I live, my pool's salt level is steadily climbing and I don't expect to ever have to add salt. I'll be looking to get rid of it in a few years.

You can do all the math you want. Many before you have done just that. There are Excel spreadsheets around here somewhere that folks have worked on. But there are a lot of variables. The general consensus is that sanitizing your pool with an SWG costs about the same as doing do manually with store-bought chlorine. One you pay for up front, the other over time. One you have to haul and store a lot of chlorine, the other not so much. So they don't pay for themselves, they are a consumable, they wear out and you will buy another. For some, like me, they do "pay for themselves" in terms of convenience. So even if I did the math, allowing for pump runtime and electricity and blah, blah, blah, and it turned out that an SWG was costing me 10 or 20% more, I'd still use it. It's that convenient. I think you'll be hard pressed to find any other SWG users here that would claim otherwise. We all love them. So you can spend hours on cost analysis. Please share your findings if you do. Or you can just go get one and save the hassle. Either way, by this time next year you'll be one of us!! ;)

Now what will pay for itself, eventually, is a variable speed pump. That is something to seriously consider. Look for rebates, sell or repurpose the old pump. And then watch your electric bill drop. (Based on someone above saying you have a 1-speed pump.)

The use of an SWG will not significantly impact testing frequency. You get to know your pool, regardless of sanitation, and your testing regime finds its rhythm. You can't stop testing because of an SWG, if for no other reason than you have to make sure it's working and providing the correct level of chlorine.

What it can do, is free you up to leave your house for multiple days. With manual dosing, which in summer needs to happen most every day, you either have to stay home, coerce someone to add chlorine for you, or use pucks. All bad. With an SWG, that you have dialed in, you can risk sneaking off for a while and your pool will stay sanitized. It's not foolproof, but the possibility of freedom exists (that's the safest way to put it)!

Not often mentioned: SWGs do not work in water below about 50° (depending on brand). Which means at some point, for some number of months, you turn off the SWG and revert to treating your pool with chlorine manually. Typically the chlorine demand during those same months drops, so it's not as big a chore as swim season, but it is something to be aware of. Unless you'll be closing your pool for winter, you'll be supplementing your sanitizing system during off-season with liquid chlorine. You'll also sometimes need to goose your pool with liquid chlorine during swim season, like right before and/or after a big pool party. So SWGs do not completely eliminate the use of liquid chlorine in all pools.



Regarding that statement, if I may, that was pretty close, although there is no actual need to "pay closer attention." Same amount of testing and adjusting as non-swg pools, but maybe different kinds of adjusting is all. And it's more important to monitor and adjust CSI as needed, in the -0.3 to 0.0 range (which may or may not be done by adjusting pH). CSI is more of an indicator of how your cell will or won't get "clogged up" than pH is. I run my pH at 7.7 to 7.8 and my cell is fine because my CSI is in range. It's not accurate to say your pH will need to be 7.5 - 7.6. Every pool is different.

Thank you very much, really appreciate the advice. Question, how often do you add salt? How often do you test?
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
4,758
Central California
Thank you very much, really appreciate the advice. Question, how often do you add salt? How often do you test?
Well, technically, salt is added every day, via muriatic acid and swimming in the pool. But I think you're asking how often I rip open a bag of salt and pour some in, and that's never. Haven't had to yet. My pool's salt level is slowly climbing on its own. Based on this first year's stat's, I don't expect to ever have to add salt.

I test ph and FC every few days. I've gone as long as 7 days, but I try to test those two every two or three days, and make sure to before any guests or kids jump in. Both have been rock solid for months, thanks to automation.

I test everything else about once a month. I've stabilized CH, it doesn't move much. TA I leave alone and only check it to make sure it hasn't gone haywire, which it hasn't. CYA dropped a little this summer as expected. I manipulate pH a little to keep CSI in check, because water temp is not particularly stable: temp really affects CSI, and CSI is easy and fast to adjust by moving pH.

Like the others, I test salt about once a month. But it gets tested by the SWG every day. That test is not particularly accurate, but the results transmit back to my automation controller, which would alert me if salt was out of range. So in essence, I know everyday that salt is OK.
 

Chuckiechan

Well-known member
Jun 10, 2014
448
Roseville, CA
Sorry... Saturation Index. It's calculated easiest using Pool Math and is an indicator of the condition of your water.

Pool Math Program said:
Calcite Saturation Index - requires pH, TA, CH, CYA, Temp, uses Borate, Salt
Less than -0.6 is suggestive of problems for plaster, tile, stone, and pebble pools.
Greater than 0.6 is suggestive of problems for all pools.
I'm not sure how important it is with vinyl, but is is important AFAIK with all SWG's.