How to handle this white line ?

[Sgalloway99]

First year pool owner opened in May. I’ve always noticed a small water line of scale or something and have brushed and scrubbed throughout the warm months. Too cold to swim over last month and line seems to be getting worse. Any suggestions on managing it? I feel like I’m keeping my chemistry in check thanks to this group. Pics attached

 

[mas985]

Is that in the spa? The bubbles in the spa tend to make PH rise so CSI ends up on the high side which can encourage scale. Post a full set of results including CSI.

 

[Sgalloway99]

This is my pool. All the way around basically the same. My test results are linked in my profile so yon should be able to see history. Let me know if not. I can see when I click

 

[mas985]

CSI is a bit on the high side. I target around -0.3 to keep scale down. That means a 7.5 PH for your current levels.

 

[Sgalloway99]

Will it resolve on its own? Or how do I get it off. Nothing has worked well for me including 50/50 Acid. CSI has only started climbing as water temp has dipped. Maybe that’s why it’s (scale) seems to have worsen. Pool migrates to 7.8 pretty fast. New pool - I tend to drop it weekly.

 

[mas985]

My experience with tile line scale is that it is very difficult to remove even with acid which helps but never seems to eliminate it.

There are services that will remove it with beads. Short of that, I have tried 200 grit wet/dry sand paper with some success.