Considering SWG for Vinyl Liner Pool

Ck28

Bronze Supporter
Mar 19, 2017
3
Rockaway, NJ
I am considering adding a SWG to our 26K gallon Vinyl liner pool in NJ. I grabbed 6 containers of chlorine from the pool store before NJ shut non essential businesses with intentions of opening beginning of April, depending upon weather. My current setup is dosing liquid 12.5% hypo direct from 2.5 gallon containers via a stenner peristaltic pump. This has worked well in the past.

I have some concerns about the SWG and corrosion of the pool walls behind the liner, handrails, and concrete surfaces. Are these concerns warranted? I know there are a few liner holes just above the water line, nothing big, so that would be my concern about wall corrosion as I am sure the walls are galvanized.

An additional issue would be the need to add acid to the pool as it seems SWG increase acid demand. I have been unable to source 20 baume Muriatic acid last year and would need to settle for 10 baume, essentially doubling my acid cost.

Any thoughts or comments are appreciated!
 

Newdude

Well-known member
Jun 16, 2019
3,721
NY
have some concerns about the SWG and corrosion of the pool walls behind the liner, handrails, and concrete surfaces. Are these concerns warranted?
1) no
2) no
3) no

Most pools already have half the salt content of a salt pool. Liquid chlorine pools that haven’t had their water exchanged (either by rain or hose) in a few years can easily have ‘salt pool’ levels.
which is half of a human tear, and 10% of the ocean.

I have more salt in my outside air than I do in the pool.

Some patios are softer material. They weather due to sunlight and moisture either way. Of course if it’s a salt pool, The pool gets blamed by the owner who doesn’t know better. And that story gets recirculated around the country again and again.


An additional issue would be the need to add acid to the pool as it seems SWG increase acid demand. I have been unable to source 20 baume Muriatic acid last year and would need to settle for 10 baume, essentially doubling my acid cost.
This one is valid, Cost wise. Most salt pools like to have a PH rise, But most owners fight it more than they need to also. Everybody tries to drop the PH back down to 7.2 and it only works for hours. If they target 7.8. It takes longer to reach 8 again for most pools. So if you do it right, the two may wash and you won’t use more acid, Or as much as you are expecting.
 

unkyjoe

LifeTime Supporter
Jun 24, 2013
199
Seguin TX
So a SWG on an AGP with a vinyl liner and steel walls will not rust out due to using a SWG? Mine will have resin top caps, top and bottom rails, a steel wall and alum-steel service panel. Opinions?
 

Newdude

Well-known member
Jun 16, 2019
3,721
NY
It won’t rust any noticeable difference from the type of water. If it rusts, it would have done so anyway. I would personally coat every inch that will rub anywhere and possibly lose it’s factory finish. Also the skimmer/return area and screw holes. Rustolium makes a few sprays that would do the trick.
 

Cincicobra

Bronze Supporter
Apr 14, 2018
78
Cincinnati, Ohio
I am considering adding a SWG to our 26K gallon Vinyl liner pool in NJ. I grabbed 6 containers of chlorine from the pool store before NJ shut non essential businesses with intentions of opening beginning of April, depending upon weather. My current setup is dosing liquid 12.5% hypo direct from 2.5 gallon containers via a stenner peristaltic pump. This has worked well in the past.

I have some concerns about the SWG and corrosion of the pool walls behind the liner, handrails, and concrete surfaces. Are these concerns warranted? I know there are a few liner holes just above the water line, nothing big, so that would be my concern about wall corrosion as I am sure the walls are galvanized.

An additional issue would be the need to add acid to the pool as it seems SWG increase acid demand. I have been unable to source 20 baume Muriatic acid last year and would need to settle for 10 baume, essentially doubling my acid cost.

Any thoughts or comments are appreciated!
I had very strong concerns about corrosion when I decided on a salt water vinyl pool, and was going to initially build a fiberglass pool because of the worries. But, fiberglass pools come with their own set of issues - so it's really a pick your poison kind of thing. In the end there shouldn't ever be salt water contacting your walls, etc if everything is serviceable in your pool. Ultimately, my pool manufacture (Latham) has a lifetime warranty and they confirmed using a SWG does not void the warranty. I researched it to the nines, which is what led me to discover this forum btw, and learned that the salt water is low on the corrosion concerns vs. PH and other factors.

Second, a properly bonded pool should resist corrosion in the steel. I also put a 5 lb zinc anode in the ground next to my heat pump, which keeps the ground moist, and attached that anode to my bonding grid. It is up for debate if that is necessary at all and the debates lean towards not necessary but it helped calm my OCD. In theory, the zinc anode should corrode before anything else as it's the most inferior metal.

As far as acid, you can pick up muriatic acid at home dept or lowes in the solvent / paint isle for $10, and I go through 2-ish gallons a summer. I think it's 20 baume.