Very localized scale - - Why and how to remove?

[Bart]

I just opened my pool and for the most part it looked great but I had some very localized patches of scale. There were 3 or 4 places around the pool where "lines" if scale have formed. They are all very similar to the attached photo - between two tiles near the surface. Last year I only had one, but this year there are a few more.

Does anyone know why this is happening in these spots and how I should remove them? Is there a way to prevent more from forming next year?

Thanks!

 

[Richard320]

It looks like effervescence. Check out some of the pictures in this thread: what-is-this-white-stuff-t34141.html

 

[Bart]

Hummmm. It might be, but I'm not sure. The photo in the link looks like it's a stain rather than a growth. Mine are "three dimensional".

The other difference is my pool is surrounded by concrete decking (not backed up to a dirt hill like in the photo) so I wonder how much rain water could actually seem in?

 

[duraleigh]

Pretty sure that is efflorescence wherein minerals migrate from behind the surface of the tile and grout onto the surface.

All you can do is clean it with muriatic acid until it stops......which can be a long time.

It's pretty common for water to be behind the stain (other side of the pool wall) as that dissolves the minerals and then allows them to migrate forward.

 

[Bart]

Thank's for the second opinion!

Another contributing factor may be that I haven't had the area between the coping and the deck sealed yet. I'm planning to do it this fall, but right now, it's pretty much an open gap.

 

[duraleigh]

it's pretty much an open gap

Good point. That certainly could be a contributor.