What to do temporarily?

[jeremycrook]

Are you still having scaling issues?

Yes.
I lowered my pH yesterday to see if that may help out, however I did notice yesterday there was some scale gathering in the wading area.

My CSI is slightly negative and from everything I have read it should not be scaling.

 

[pooldv]

Try moving it to -0.3 or -0.4. Another member had a defective swg cell from Hayward that was producing scale despite negative CSI. Hayward replaced it and the scaling went away.

 

[jeremycrook]

Try moving it to -0.3 or -0.4. Another member had a defective swg cell from Hayward that was producing scale despite negative CSI. Hayward replaced it and the scaling went away.

I did read that entire thread that you mentioned "help with scale" or something like that. I too have negative CSI (-.56), and he also lived in OKC so I thought I might be on to something. I have reached out to Jandy to see if they will replace the cell or let me try another one. My water is down to 68 degrees, and with the temps going towards high 40's at night I suppose there won't be too much time before the cell is out of it proper temperature range for functioning?

Plugging in my numbers for CSI - pH ~7.4 , TA 70 , CH 300 , CYA 40 at 69 degrees gives me a -.56. If I move pH up or down .1 it will vary from -.4 to -.7. I added some MA this weekend to lower pH to see if it would do anything and I have not taken solid numbers since. They have been staying pretty solid, but these are my best guessed numbers as of now. I will see what Jandy thinks regarding a different cell.

I also didn't know if I should choose the option for the SWG to descale every 7 hours instead of every 3? I have the 3, 5, or 7 options, I moved it from 5 to 3. Just a thought.

 

[pooldv]

I would choose the most frequent option with the thought that less scale would build up and the pieces would be smaller. Yes, it won't be long before it shuts off.

 

[jeremycrook]

So after many email exchanges with Jandy this is the final answer from them regarding my scaling issue:

"Hello,

Thank you for all the info. Our lead tech says that scaling will happen on our cells. As long as it does not get to the point where it clogs up. Every couple months you will need to see if it has a large build up. if it does then you will need to acid wash it. Otherwise some scaling is normal in the cell and there is not anything wrong with the cell and is normal and can't be completely prevented. "

I think lowering my pH below or around 7.4 might have helped a bit, however when I plug in numbers into POOLMATH I find that I get closer to zero if I go up on pH. Am I supposed to be getting closer to zero for removing scale, or should I more into the negative to better keep scale from forming?

I might try lowering TA and adding borates in the summer if there is any still present. I'm thinking my SWG is going to turn off soon due to the cooler evenings that have arrived.

 

[domct203]

So after many email exchanges with Jandy this is the final answer from them regarding my scaling issue:

"Hello,

Thank you for all the info. Our lead tech says that scaling will happen on our cells. As long as it does not get to the point where it clogs up. Every couple months you will need to see if it has a large build up. if it does then you will need to acid wash it. Otherwise some scaling is normal in the cell and there is not anything wrong with the cell and is normal and can't be completely prevented. "

I think lowering my pH below or around 7.4 might have helped a bit, however when I plug in numbers into POOLMATH I find that I get closer to zero if I go up on pH. Am I supposed to be getting closer to zero for removing scale, or should I more into the negative to better keep scale from forming?

I might try lowering TA and adding borates in the summer if there is any still present. I'm thinking my SWG is going to turn off soon due to the cooler evenings that have arrived.

The more negative your CSI, the more aggressive your water is to the surfaces it contacts. When moving CSI negative to remove scale, I believe that you are in fact removing the plaster that the scale is attached to, so don't go crazy with very aggressive CSI moves. I do not own a plaster pool, nor have direct experience maintaining one, but from what I have read, any more negative than -6 is considered somewhat aggressive CSI, with over -1.2 extreme.

Hopefully some experts will chime in and correct any info I have wrong.

[EDIT]Here is some good reading:
http://www.troublefreepool.com/threads/122703-Scale-Removal

 

[pooldv]

You want your CSI to be between -0.3 and 0, that won't hurt the plaster at all. If the cell still scales you can lower CSI to as low as -0.6. There is slightly more risk of aggressive water at -0.6.

Our water here has high potential to scale also. Everyone's shower and coffee pot has scale build up. I haven't needed to clean my SWG cell in 5 summers.

More here, Pool School - Calcium Scaling