Question about bubbles being produced by my SWG

PhantomF

Active member
Apr 2, 2017
29
Tampa, Florida
#1
My new pool was completed at beginning of March and I noticed right away that at the closest return jet there are always bubbles coming out when the pump is running. My PB did a pressure check and was perplexed about it and had me turn the Hayward variable speed pump up 400 RPM which helped a bit but bubbles still were coming out just more spaced out. Eventually I noticed it was the Aquarite SWG that was producing the bubbles as they would disappear when it was turned off. From what I've found there is really nothing you can do to prevent this as it's normal for the SWG to produce hydrogen and chlorine gasses during operation. The problem is most likely that this return jet is too close to the SWG. My question is does this bubbling aerate the water and thus increase the pH the same as air bubbles from an air leak would do? It seems my pH is constantly high and I'm having to add acid every few days to bring it down. Thanks!
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,270
Pleasanton, CA
#3
Most of the gas that reaches the returns should be hydrogen gas because it does not dissolve in water. Most if not all the chlorine gas should be dissolved into the water by the time it reaches the returns.


My question is does this bubbling aerate the water and thus increase the pH the same as air bubbles from an air leak would do? It seems my pH is constantly high and I'm having to add acid every few days to bring it down. Thanks!
Yes it does. This is normal behavior for those of us with SWGs.

What might help is lower TA to a point where PH stabilizes. However, if you have high TA fill water that you rely upon, this may not help much since TA will eventually rise again.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
10,888
Bedford, TX
#4
Phantom,

Welcome to TFP... A Great resource for all your pool and SWCG questions... :wave:

While it is true SWCG's will cause the pH to increase, I suspect there are a couple of other reason's you are having to add acid so often.

1. Your pool is new. Assuming it is a plaster pool, new plaster will initially cause a pH increase for the first 6 months to a year.
2. I suspect that you are trying to keep your pH at 7.2, when most SWCG pools like to run at about 7.8. At 7.8 I can often go several weeks without adding acid, at 7.2 I can go about 30 seconds.. :cool:
3. Water features.. If you have any water features or a spa spillover, this will also cause your pH to increase due to aeration.

You did say something that worries me.. You said your PB had you increase your pump speed to "400"... Most SWCG's will not turn on the flow switch below about 500 or 600 RPM, so that makes me think that your flow switch is not working or not wired correctly. This is a little dangerous as the whole purpose of the flow switch is to make sure that you have enough flow so that the chlorine gas does not build up and explode... Unlikely, but safety issue anyway.

Thanks for posting,

Jim R.
 
OP
OP
P

PhantomF

Active member
Apr 2, 2017
29
Tampa, Florida
#5
Yes it does. This is normal behavior for those of us with SWGs.

What might help is lower TA to a point where PH stabilizes. However, if you have high TA fill water that you rely upon, this may not help much since TA will eventually rise again.
Thanks I figured it would be part of the reason pH is rising. My TA is a bit on the high side at around 140 currently so I could try bringing it down some. I haven't tested TA on my source water so I'll check that out as well.


Phantom,

Welcome to TFP... A Great resource for all your pool and SWCG questions... :wave:

While it is true SWCG's will cause the pH to increase, I suspect there are a couple of other reason's you are having to add acid so often.

1. Your pool is new. Assuming it is a plaster pool, new plaster will initially cause a pH increase for the first 6 months to a year.
2. I suspect that you are trying to keep your pH at 7.2, when most SWCG pools like to run at about 7.8. At 7.8 I can often go several weeks without adding acid, at 7.2 I can go about 30 seconds.. :cool:
3. Water features.. If you have any water features or a spa spillover, this will also cause your pH to increase due to aeration.

You did say something that worries me.. You said your PB had you increase your pump speed to "400"... Most SWCG's will not turn on the flow switch below about 500 or 600 RPM, so that makes me think that your flow switch is not working or not wired correctly. This is a little dangerous as the whole purpose of the flow switch is to make sure that you have enough flow so that the chlorine gas does not build up and explode... Unlikely, but safety issue anyway.

Thanks for posting,

Jim R.
Thanks for the welcome! My PB did mention that the plaster walls would cause the pH to increase for a while until they are completely cured. I was actually aiming for pH to be between 7.4 and 7.6 but it's always 7.8 to 8.0 when I test every few days. You think it's safe to just leave at 7.8 then? I do have a water feature as well which I'm sure is adding to the issue. My PB had me increase the pump speed up by 400 RPM, to 2600, not set it at 400RPM :)
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
10,888
Bedford, TX
#6
Phantom,

Well that makes me feel better... :D

I normally run mine at 1,200 RPM when generating chlorine.

Yes, leaving pH at 7.8 is just fine, the longer it stays there the better. I only add acid when it gets above 7.8....

Jim R.
 
OP
OP
P

PhantomF

Active member
Apr 2, 2017
29
Tampa, Florida
#7
Phantom,

Well that makes me feel better... :D

I normally run mine at 1,200 RPM when generating chlorine.

Yes, leaving pH at 7.8 is just fine, the longer it stays there the better. I only add acid when it gets above 7.8....

Jim R.
Thanks I will keep pH at 7.8 from now on then.

Wow if I set my pump that low I would have huge hydrogen bubbles coming out of the jets. I tried 1500 and it was pretty bad, less frequent but very large bubbles every once in a while. I imagine if I had a flame going there it would make a nice little bang haha
 

Divin Dave

TFP Expert
LifeTime Supporter
Oct 2, 2013
5,194
Longview, Texas
#8
pH has a tendency to rise naturally, so you shouldn't attribute quick pH rise specifically to the bubbles produced by the SWG. If you have a plaster pool, the plaster will also be a heavy contributor. Especially if the plaster is fairly new.

With your TA at 140, you certainly should expect pH to rise fairly quickly just because of that. Im sure you can slow it down considerably by working on your TA though.

Some of us are lucky and found the sweet spot with our TA and other chemistry and dont have very much pH rise at all, even with the bubbles produced by the SWG.
 
OP
OP
P

PhantomF

Active member
Apr 2, 2017
29
Tampa, Florida
#9
pH has a tendency to rise naturally, so you shouldn't attribute quick pH rise specifically to the bubbles produced by the SWG. If you have a plaster pool, the plaster will also be a heavy contributor. Especially if the plaster is fairly new.

With your TA at 140, you certainly should expect pH to rise fairly quickly just because of that. Im sure you can slow it down considerably by working on your TA though.

Some of us are lucky and found the sweet spot with our TA and other chemistry and dont have very much pH rise at all, even with the bubbles produced by the SWG.
Thanks, whats a good target TA? 80-100? Best way to lower it is with Muriatic acid right?