why is Mustard Slam with liquid chlorine taking out pool surface, see pics

[RosieMa]

we did a shock (20) followed by a mustard shock (29.5) using liquid chlorine. Why is that taking out our pool floor surface?

 

[jblizzle]

Welcome to TFP!!!

How much time passed between those pictures?

Can you post a full set of test results?

That almost looks more like calcium scale buildup to me, or maybe discoloration due to metals, or both ... more so than loss of pool surface.

 

[duraleigh]

What was your CYA when you elevated the chlorine?