Does a SWG cause bubbles from the returns?

Goob

Gold Supporter
Oct 20, 2015
118
Magnolia, TX
I have small bubbles coming out of 1 and sometimes 2 of my pool returns.

I don’t remember the bubbles being there from the beginning 2 years ago. I noticed it this year about the same time the pool builder came out and put in a new valve which was about the same time warranty work was done on my IC60 (not replaced). That warranty work required replacing some circuitry and I don't think anything was done with the plumbing part of it.

I’ve been back and forth with the pool builder over the last couple of months about what could be causing it. He places blame on cavitation and the fact I use a robot cleaner. The cavitation, he says, is causing bubbles to collect in the tubing because my equipment is lower than my pool and the air is slowly being pushed out throughout the day with the lower pump speed. With the robot cleaner, I don’t have my pump ever running at high speeds like owners who use a pressure side cleaner, again said by pool builder. Either way, he claims that there is nothing to worry about. I can’t find any leaks anywhere with the pool equipment and my pump lid keeps a small bubble that doesn’t grow with the pump running or sitting.

Recently, I had to do a SLAM with the pump running continuously and the SWG off. Guess what? The bubbles went away within the hour and didn’t come back until I turned the SWG on after the SLAM process- bubbles reappeared within 5 mins. Turned the SWG off, they went away again. Turned the SWG on, they reappeared.

Is this normal? I think I’ve read that the SWG can produce some gassing, but I would have thought the bubbling would be much smaller and less of it.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
9,754
Northern NJ
A SWG cell makes chlorine gas and hydrogen gas. The chlorine gas dissolves pretty fast and you won't normally see any coming out of the returns. Hydrogen gas does not dissolve very well. The gas coming from the returns is hydrogen. The only time that you can see chlorine gas is when you have a clear cell and can see the chlorine gas and hydrogen gas being generated at the plates.
 
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Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,206
Bedford, TX
Goob,

I'm pretty sure your pool builder is the "goob"... :)

Sounds like normal hydrogen gas bubbles from the SWCG to me also..

When running at low speed, what does it look like under your pump lid? As long as you have a few bubbles and not froth, then it is not a pump issue.

Whether I get tiny bubbles or larger bubbles at the return seems to depend on where I have the eyeball pointed.. If the gas can flow out easily, then I get very small bubbles, but if there is a place that can trap the gas, it seems to come out in larger bubbles.. And, just like you, the bubbles are only there when the cell is making chlorine.

What speed are you running your pump?

When was the last time you actually removed the SWCG for a scale inspection??

Thanks,

Jim R.
 

Goob

Gold Supporter
Oct 20, 2015
118
Magnolia, TX
Thanks all!

Goob,

I'm pretty sure your pool builder is the "goob"... :)

Sounds like normal hydrogen gas bubbles from the SWCG to me also..

When running at low speed, what does it look like under your pump lid? As long as you have a few bubbles and not froth, then it is not a pump issue.

Whether I get tiny bubbles or larger bubbles at the return seems to depend on where I have the eyeball pointed.. If the gas can flow out easily, then I get very small bubbles, but if there is a place that can trap the gas, it seems to come out in larger bubbles.. And, just like you, the bubbles are only there when the cell is making chlorine.

What speed are you running your pump?

When was the last time you actually removed the SWCG for a scale inspection??

Thanks,

Jim R.
The pump lid has a bubble about the size of 3 quarters that doesn't move much while the pump is running. It doesn't seem to change from day to day.

My pump is running at about 1800 rpm. I swear I had it at a lower speed last year (1500 rpm, maybe 1300) but I was getting a no flow error on my SWG with those settings this spring.

I haven't removed the SWCG since the end of last year for cleaning. I plan on doing it again in about a month as my water temp drops.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,206
Bedford, TX
Goob,

When did you clean your filter? Assuming it worked at 1300 before, then the main reason that you now get a low flow light is because the filter is dirty..

I run my pump at 1250 RPM.. but I do not have a heater, so I would assume you would need to run at 1500 or so, to close the flow switch.

Your SWCG could also be full of scale (If you don't watch your CSI..) and that could cause low flow..

I clean my filter and inspect my cell in the spring, before the pool season, and in the fall, after the pool season, but always when it is hot enough to get soaking wet.. :mrgreen:

Thanks,

Jim R.
 

Goob

Gold Supporter
Oct 20, 2015
118
Magnolia, TX
Goob,

When did you clean your filter? Assuming it worked at 1300 before, then the main reason that you now get a low flow light is because the filter is dirty..

I run my pump at 1250 RPM.. but I do not have a heater, so I would assume you would need to run at 1500 or so, to close the flow switch.

Your SWCG could also be full of scale (If you don't watch your CSI..) and that could cause low flow..

I clean my filter and inspect my cell in the spring, before the pool season, and in the fall, after the pool season, but always when it is hot enough to get soaking wet.. :mrgreen:

Thanks,

Jim R.
Clean the filter twice a year- May and November- was one of the early thoughts on the bubbles causing me to take the filter assembly apart a couple of times before I ruled it out.

I plan on cleaning the SWCG next month along with the filter. I'm interested to see if I find anything there although I watch the CSI really close and the SWCG is new.

I guess it could just be that I don't remember the setting correctly.

Again, appreciate all the help. This forum is well worth what I have contributed.