Quote Originally Posted by Katy-Texas
Hi Pat

You say that I may want to lower SWCG from 50% I assume to extend it's life, but then I'd need to circ longer thus more power, guess it's a trade off.

The function of the SWCG is to generate chlorine, but in so doing, scale tends to build up on the cell membranes. This is removed by reversing the polarity to the membranes, and for this to work properly, the SWCG has to run at least 2 reversals to keep the membranes clear. Check with your manual for the default reversal settings, (usually 4 hours each, total 8) or call your SWCG vendor for more information on this.

Keep pH in 7.2-7.6 so don't think that's why etching.

Similar to you, pool builder added salt about 1 month after plaster & fill.

Thanks for ideas . . . cheers.
Hope this helps.

Pat