White markings on coping?

[NaCLTPool]

Does anyone know what the white stuff is on the coping? I’ve only seen it one on one block and didn’t appear until recently.

 

[PoolStored]

Pictures would help us with any diagnosis...

 

[Newdude]

While waiting for pics, my coping bled efflorescence for over a year. They came that way and it was really bad at first so I can only imagine they sucked up various mineral dust at the distributer. The patio was equally as dirty/dusty for that time and had i not seen the coping get unwrapped already chalky, I would have blamed the patio runoff. But it may have contributed to the length of time it took to wash it all away.



I also get white marks from the safety cover seams.

 

[NaCLTPool]

While waiting for pics, my coping bled effervescence for over a year. They came that way and it was really bad at first so I can only imagine they sucked up various mineral dust at the distributer. The patio was equally as dirty/dusty for that time and had i not seen the coping get unwrapped already chalky, I would have blamed the patio runoff. But it may have contributed to the length of time it took to wash it all away.

View attachment 628824

I also get white marks from the safety cover seams.

Sorry, was having issues posting on my phone.