Converting to SWG... the good, the bad and the ugly??

OHcabanaboy

Well-known member
Jul 3, 2016
94
Delphos, OH
I've been doing as much reading about SWG's as I can possibly stand. I tend to over analyze purchases like this. But when I'm buying something I want to make sure I'm getting the most bang for my buck meaning I'll reduce the time I spend testing and increase the amount of time I spend floating... or drinking a beer and watching my wife and kids floating.
The good seems to break down to "no more buying and storing chlorine" and "less monitoring of chlorine" (notice I don't say no more...)
The bad, based on my reading so far, seems to be that there's an increased need to monitor PH. So it seems to me you trade monitoring both Chlorine and PH for just monitoring PH on a semi regular basis.
The ugly seems to be that I've found a lot of articles that mention corrosion to metal pools like my AGP with a metal top rail. It seems like adding an anode is recommended to sacrifice it rather than the metal that makes up the pool.

So what's right? Is there more risk of corrosion going to SWG? Do I need to add a sacrificial anode to the system to prevent corrosion? Beyond there being no more storage of chlorine bottles, is there really a greater benefit to SWG vs just making a chlorine injection system with a dosing pump that adds chlorine throughout the day?

Here's an article that absolutely blew my mind Is Salt Water Bad For Your Pool?
 

Newdude

Well-known member
Jun 16, 2019
1,482
NY
is there really a greater benefit to SWG vs just making a chlorine injection system with a dosing pump that adds chlorine throughout the day?

The going to the store part, the lugging jugs part and the filling the injection system part. Most ‘chlorine’ pools already have a lot more salt as a byproduct than the the average non-TFP-er realizes. People will probably argue until the end of time if adding a little more makes a difference. A good start would be to look up everything you can about your specific model and see if it was prone to rust in the first place. The people that had problems after switching may have had problems either way but you will never convince them of that. Conversely, if there are plenty of good conversion stories, you can rest easier about it.
 

Dtkokay

Member
Dec 31, 2019
14
Houston, Texas
One potential negative of a SWG is that it will not produce chlorine (EDIT) if the water temperature is too low. If you need chlorine, that means you'll have to find a way to add it, such as with liquid chlorine. Then again, if the water temperature is low, it's because it's winter and you may not need to add chlorine anyways.

I'm at the doorsteps of building a pool and will be going with a SWG. The builders I met with highly discouraged this, but I haven't been able to find any first hand complaints from people that use a SWG, including friends. On the other hand, I have read plenty of stories about problems with managing high CYA from dichlor tablets.
 
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jseyfert3

Well-known member
Oct 20, 2017
393
South-Central WI
The bad, based on my reading so far, seems to be that there's an increased need to monitor PH. So it seems to me you trade monitoring both Chlorine and PH for just monitoring PH on a semi regular basis.
Not if you've been using liquid chlorine as TFP recommends, because liquid chlorine is basically pH neutral. Most people need regular acid additions to maintain their pool. If you're not TFP you likely add FC using trichlor, which is acidic, so you'd be adding acid without knowing it, so switching from using primarily trichlor to SWCG you would likely see an large increase in pH rise. But switching from liquid chlorine to SWCG will not change how often you need to check or adjust pH in the slightest.


Here's an article that absolutely blew my mind Is Salt Water Bad For Your Pool?
I skimmed that and it appears there is a bunch of bunk in there. I could address some of it later if someone else doesn't do it first.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
15,049
Bedford, TX
Ocb,

Just for reference, I have three gunite saltwater pools.. They have been saltwater pools for about 9 years, 7 years, and over 5 years.. I have had zero corrosion or any problems related to saltwater. If I built another 100 pools they would all be saltwater pools.

I have heard all the stories about how bad saltwater pools are , but when you get down to the details, you find that it is hard to find any first hand info.. It is almost always a case of "My friend, had a friend , who married a guy who had a problem with his saltwater pool"... :mrgreen: Even the few first hand reports are all from owners that did not have a clue how to operate their pools.. They did nothing to two years and could not understand how there could be any problems. Sigh!!

I must admit that I have no experience with Above Ground Pools, but I can't see where it would make much difference. In my opinion, if an ABG is going to rust, it will do it whether it is a saltwater pool or a standard chlorine pool.

Thanks,

Jim R.
 

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
875
Rancho Cucamonga, CA
The advice I've seen here is, if your pool is properly bonded, risk of corrosion is greatly reduced and there is no need for a sacrificial anode. I assume that includes metal AGPs.

One other thing to consider; liquid and solid forms of chlorine add salt to your pool as a byproduct. I had my current pool for three years before I switched over to a SWG. My salinity was 1200 ppm without ever adding an ounce of pool salt. That's roughly one-third of what's required for a SWG, but salt is salt. I like to float and drink beer too, so the SWG works for me. That said, as (you being) an owner of a metal pool, I understand your concerns.
 

AusPhil

Well-known member
Jan 23, 2018
100
Canberra ACT
But switching from liquid chlorine to SWCG will not change how often you need to check or adjust pH in the slightest.
This is not 100% true and is pool dependent....... my 12x24 vinyl AGP got started with tri-clor (deliberate to intro cya) and then we changed to 12.5% chlorine, at that point we stopped fighting ph decrease to needing to add some acid due to small ph rise..... swapped over to a SWCG about 8 weeks or so ago and i see a slight increase in ph movement and the PH likes to run around 7.8 with the SWCG whilst with the chlorine only it was closer to 7.4 regularly ....
Weirdly my testing frequency has gone up a little whilst i learnt what the SWCG was doing but it's reducing again...

The good: more consistent levels, ability to go away for days/weeks without stressing, no need to remember each day......SWCG will give you some of your life back.

Rust concerns: over played by builders and concerned people .... underplayed by others, the reality is likely somewhere in the middle as it always is..... put bare iron/steel out in the desert and it will still rust just at a slower pace than the same part sitting in the sea ... will your pool rust before it's useful life is over, most likely not...
My cheap oem supplied pool ladder for the AGP started to rust inside the joints over winter.. OUTSIDE the pool and before salt levels had been brought up to SWCG levels..... has it got worse now it's back in the pool with the "salt" water, well i would say it isn't better :) it's still rusting ..... but there is no way i would blame the salt levels needed for the SWCG.
 
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AusPhil

Well-known member
Jan 23, 2018
100
Canberra ACT
Ocb,
I must admit that I have no experience with Above Ground Pools, but I can't see where it would make much difference. In my opinion, if an ABG is going to rust, it will do it whether it is a saltwater pool or a standard chlorine pool.
Thanks,
Jim R.
Jim i agree that rust will take hold no matter what on a metal AGP as the reality is that any bare iron/steel will rust even in a dry desert. What i expect does change though is the rate of rust ...
I wonder if some simple experiments could be done on controlled salinity samples to see it the rust rate changes much at the lower salinity levels
 

Rattus Suffocatus

Silver Supporter
Jun 5, 2019
484
Corona de Tucson, AZ
A salt pool is, what? 3000 ppm? The sea on average is 35,000 ppm.. So the amount of salt is only considered very mildly corrosive. It's nowhere near seawate. I suspect maybe a very slight increase in the rate of corrosion but probably not enough to notice nor negate the convieience of having a cell.

Have the lid fly off of some Hasa in the car during a turn one day and have to clean it up on the side of the road like I did last time and then you will absolutely think about adding a cell.

Now, does anyone have a suggestion of what the best DIY cell is at this point? I need to start budgeting for one myself.
 

jseyfert3

Well-known member
Oct 20, 2017
393
South-Central WI
This is not 100% true and is pool dependent....... my 12x24 vinyl AGP got started with tri-clor (deliberate to intro cya) and then we changed to 12.5% chlorine, at that point we stopped fighting ph decrease to needing to add some acid due to small ph rise..... swapped over to a SWCG about 8 weeks or so ago and i see a slight increase in ph movement and the PH likes to run around 7.8 with the SWCG whilst with the chlorine only it was closer to 7.4 regularly ....
Weirdly my testing frequency has gone up a little whilst i learnt what the SWCG was doing but it's reducing again...
True. I should have said "not much change". I don't actually have a SWCG. Chem Geek showed how the reactions are basically (not completely) neutral, but pointed out how it's not known why pH rise with a SWCG was caused. Still, that's not a strong effect, and I will stand by my original hypothesis that the article owner would be talking about using trichlor, since that seems to be used almost exclusively by people that don't practice TFP, and switching from trichlor to SWCG. For many people, at least in the US, if you switch from trichlor to anything you will see a "pH rise" since the fill water has so much TA.

put bare iron/steel out in the desert and it will still rust just at a slower pace than the same part sitting in the sea
Yes, cause you get dew in the desert. :) But below a certain humidity level, bare steel/iron will not rust. Depending on the specific metal type this level is 50-80% RH. Below that point you won't get any rust.
 

setsailsoon

LifeTime Supporter
TFP Guide
Oct 25, 2015
1,781
Stuart/FL
Ocb,

Don't do what I did. I didn't listen to Jim R (see post #7) so I lugged jugs for 4 extra years. Finally I succumbed Feb of last year. It makes everything soooo easy. Yes I still have to take care of pH but I did borates at the same time and even pH adjustment is about half as frequent.

Either system works but salt is just way easier. A bonus is that my wife loves the feel and won' t ever let me go back. So you can do this the smart way or do what I did. I strongly recommend the former.

Chris
 

ar26pt2

Member
Apr 15, 2016
23
Atlanta, GA
I converted my pool to SWG a couple weeks after I bought the house with it. Never had a pool before. Im a fairly Handyperson so I learned quick. During warm season I check pH and FC once a week, but often forget, hardly have to do anything, add muriatic acid twice monthly/Usually just a a guesstimate. Calcium, salt, cya, bicarb adjustments usually just at pool open. I have had it green once in 3 seasons- right at beginning when cya was jacked up high from prior owner. Early In season I add bleach until it warms up and swg working. One year the sensor on the swg failed and I replaced it. It is basically easy and I wouldn’t have it any other way.
 

carnivalday

Gold Supporter
Oct 25, 2017
176
Ocala, FL
This part of the article was hilarious to me: A salt water pool still requires every last bit of maintenance, care and upkeep that a traditional chlorine pool needs. The only difference is that you no longer need to buy and transport chlorine products (for the most part). Thats like saying "a bicycle still requires the same maintenance that an automobile needs. The only difference is you dont have to buy gas, do oil changes, and rotate wheels.
 

OHcabanaboy

Well-known member
Jul 3, 2016
94
Delphos, OH
Not if you've been using liquid chlorine as TFP recommends, because liquid chlorine is basically pH neutral. Most people need regular acid additions to maintain their pool. If you're not TFP you likely add FC using trichlor, which is acidic, so you'd be adding acid without knowing it, so switching from using primarily trichlor to SWCG you would likely see an large increase in pH rise. But switching from liquid chlorine to SWCG will not change how often you need to check or adjust pH in the slightest.
Good! Then I'll only have to adjust PH once during a season because that's all I have to adjust it now!
 

OHcabanaboy

Well-known member
Jul 3, 2016
94
Delphos, OH
I converted my pool to SWG a couple weeks after I bought the house with it. Never had a pool before. Im a fairly Handyperson so I learned quick. During warm season I check pH and FC once a week, but often forget, hardly have to do anything, add muriatic acid twice monthly/Usually just a a guesstimate. Calcium, salt, cya, bicarb adjustments usually just at pool open. I have had it green once in 3 seasons- right at beginning when cya was jacked up high from prior owner. Early In season I add bleach until it warms up and swg working. One year the sensor on the swg failed and I replaced it. It is basically easy and I wouldn’t have it any other way.
This is the part that concerns me. This is the time I most want/need a system that feeds or generates automatically. The rest of the summer when my wife or I are around, it's a matter of walking out and adding about 1/2 gallon every night. This is why I'm debating SWG vs designing a system to automatically dispense chlorine throughout the day. I could program a pump to dispense a measured amount two or three times throughout the day and keep my chlorine levels at a pretty steady level but that requires me buying and storing chlorine which I'd like to get away from.
 

OHcabanaboy

Well-known member
Jul 3, 2016
94
Delphos, OH
The advice I've seen here is, if your pool is properly bonded, risk of corrosion is greatly reduced and there is no need for a sacrificial anode. I assume that includes metal AGPs.
This is what I've been reading more about. I know my pool isn't properly bonded... but it will be before the start of the next swim season!

One other thing to consider; liquid and solid forms of chlorine add salt to your pool as a byproduct. I had my current pool for three years before I switched over to a SWG. My salinity was 1200 ppm without ever adding an ounce of pool salt. That's roughly one-third of what's required for a SWG, but salt is salt. I like to float and drink beer too, so the SWG works for me. That said, as (you being) an owner of a metal pool, I understand your concerns.
Yeah I'm aware of the added salt with liquid chlorine. I actually add salt to my pool (not a lot) early in the season then add a bit more after the kids are using the pool. I add the salt to soften the water so their skin doesn't get dried out like it used to before I started adding a small amount of salt.

Keep the replies coming! I'm weighing this out and trying to find all the positives and negatives. So far not working at colder temps is a deal breaker depending on what the water temps need to be for it to operate. I open early and close late typically so it wouldn't be reducing my workload by much early on.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,752
Laughlin, NV
Depending on brand of SWCG, most have a lower temp limit of ~55F water temperature. Some a little below that, some a little higher.

At that water temperature, you should only need to add liquid chlorine every 3 or 4 days, at most, to maintain a proper FC.
 

homegameroom

Bronze Supporter
Sep 23, 2015
191
Sunrise,FL
I bought and installed my SWG from Inyo Pools. They will warranty a homeowner installation, and their prices were competitive. I was on the fence (and even turned my nose up at my friends' saltwater pools) but I am a HUGE convert now and sing the praises of SWCG to anyone who will listen! I do occasionally add acid, but I also have a waterfall that runs my pH up.

I can leave town for a week and never worry about coming home to a green pool. I have no anxiety as to whether I have enough liquid chlorine lying around or not. And the water feels great!