Salt cell scaling despite keeping negative CSI, why?

[aztodd]

I have been battling scaling in my SWG. I've been careful about keeping my CSI slightly negative, but still lots of calcium buildup. Granted my CH is getting really high and I'll need to drain soon, I still just don't understand why I'm getting so much scaling even though I believe my pool chemistry is where it needs to be according to pool math. How far in the negative do I need to be to ensure I don't get any scaling?

 

[mknauss]

What is your TA?

 

[aztodd]

Currently 50

 

[mknauss]

That is surprising. CH must be over 1000.

Time to drain.

 

[aztodd]

Yeah, last measurement was 900 but it's very high. I'll just switch to liquid chlorine until the end of the season then drain.

 

[aztodd]

I was wondering how much the speed of the pump while the swg is active would affect the chemistry inside the cell. Does the pump need to be at a high speed to make sure that the water doesn't get too warm in there? Or is the difference going to be negligible between 1500 and 2500 rpm.

 

[mknauss]

No difference.

 

[proavia]

Your FC is flirting with minimum for SWG at CYA 70.
Some of your PoolMath results even show it fell below minimum.

Since you are now using liquid chlorine, treat the pool as a non-SWG pool and dose accordingly.
FC/CYA Levels