After adding salt to my pool, I've been getting noticeable scaling on the grout of my tile spa overflow. According to the pool calc, I have been well in the negative CSI range so I'm surprised this would be occurring. It's easily cleaned with 10:1 acid wash, but I would prefer to prevent than clean. Is this normal for any type of spillover that runs periodically? Do I need to adjust anything to better handle a spillover that runs 8+hrs a day?
TA 100 - this just recently went up from 75 in less than a week
CH 390 - this also has risen steadily from around 270 [plaster/pebble is about 6 weeks old now]
CSI -.31 at 70F