Salt Generator Bubbles Cloud the Pool

[Scout101]

Moved from here.
Bumping this vice starting a new thread, as seeing same issue. Finished SLAM, adjusted my chemicals to optimal (cya will take a bit to catch up) and installed brand new tcell15 to replace a dead sat cell. When it is operating, I get a cloudy discharge from the returns. After the swg goes into standby, clears pretty fast. Is there any kind of ‘burn in’ period or something with new cells? Old one never did this. Hoping it will go away, but can’t be ok with a swimming pool I can’t see into because the swg is running….
Water temp is about 74, salt reading 3000 and should climb to 3300 or so based on what I added. Ph 7.5, TA 70, FC drifting down from 14 at SLAM. Nothing really stands out as to why this would happen other than brand new swg…

 

[mknauss]

This seems to happen in the early year under certain water conditions, typically with cool water temperatures. No relationship has been made based on age of cell.
It clears itself in the near term.

 

[Scout101]

Sounds good, hopefully just goes away. Gets pretty milky with the cell running, but clears pretty quickly after it powers off. Never saw with old cell (both authentic Hayward cells), but old one was quite old and fading for years, so this one ought to be at peak performance

 

[JoyfulNoise]

Is your pump single speed ?

 

[Scout101]

Yes, single speed 1.5hp. Also brand new this season. SuperPump

 

[JoyfulNoise]

Any idea what your flow rate is?

My guess is that a single speed pump pushes water so fast through the cell that only microscopic bubbles of hydrogen gas form and that gets transported away too quickly for them to coalesce. Then they basically stay suspended in solution because they are too small for the buoyancy force to let them float up to the surface. This then leads to the cloudiness you see. There may be other factors involved like water temperature or suspended fine solids that makes the issue more pronounced.

A variable speed pump would allow one to test this theory a bit.

 

[Scout101]

Happy to report that it seems to have cleared up already. Either as water chemistry came up to ‘good’, warmed up slightly, or the new cell burned off whatever was on it from the factory. Couple tiny drops/leaks to straighten out in the system, but otherwise good to go

 

[JoyfulNoise]

Yeah, who knows how things are assembled overseas. Many times with PVC materials, they are manufactured with release coatings to make it easier to mold them and then as they are assembled they get coated with machining oils and other junk. I used to work closely with a machine shop to do custom fabrication work and many of our sub-components bolted right on to sensitive analytical equipment. The machine shop had a process line dedicated to cleaning finished parts that used several different vapor degreasing techniques to ensure that there were no contaminants once finished. Stainless steel components would undergo electrolytic polishing to make mirror-finished surfaces that were free from particulates, cutting oils, burrs, etc.

I sincerely doubt pool equipment makers go to any such troubles … you probably count yourself lucky to not find chewing gum stuck to it somewhere….

 

[bmoreswim]

My new Hayward T-Cell-15 is a micro bubble machine. Installed yesterday. I can’t remember if the old one did too at some point. I mostly remember larger bubbles.

 

[JoyfulNoise]

My new Hayward T-Cell-15 is a micro bubble machine. Installed yesterday. I can’t remember if the old one did too at some point. I mostly remember larger bubbles.

Can you play around with the pump speed to see if that has an impact?

 

[bmoreswim]

At 1725 RPM’s the stream of micro bubbles is clearly visible. At 2760 and 3450 they are no longer visible.

 

[JoyfulNoise]

At 1725 RPM’s the stream of micro bubbles is clearly visible. At 2760 and 3450 they are no longer visible.

Interesting … turbulent mixing may be playing a role here. We’d need @mas985 to calculate some Reynolds Numbers for us in both the plumbing as well as inside the SWG. The cell is a series of parallel plates spaced only a few millimeters apart. Perhaps the flow is turbulent enough at high pump speeds to mix the bubbles more efficiently …

 

[mas985]

The amount of gas that is generated by the cell is the same for both speeds but the amount of water is clearly different so one would expect the density of the gas bubbles to be different. While you may not see the bubbles at higher RPM, I suspect they are still there, just much smaller.

As for turbulent flow, it is considered turbulent pretty much at all but the very lowest flow rates but certainty higher flow rates may dissolve more gas than slower rates.