Help! Is this algae or what?!

[eikotsai]

Our pool wall has this super odd stain spot. It is brown like rust, and cannot be brushed off. We suspect it's algae so put in lots of shock, chlorine or algaecide, but still doesn't work. Every morning it has orange stuff growing out, and after we brush the orange stuff will be gone but later will grow back again. We even drained water and scrubbed chlorine tablet on the surface. It still didn't kill it. Can someone please help us here? We are desperate. Our pool guy said he never saw this kind of algae before.

Attached are some pictures for more info.

 

[Newdude]

It looks like a piece of rebar sticking through. See if a magnet sticks to it.

The repair is done with a full pool. They go down and patch the area slightly bigger than the rebar. It won't be perfect but noone will ever see such a small blemish. Except for you of course.

 

[eikotsai]

Hi. Thanks for your reply. I'm not sure if it's a rebar coz something orange grows out of it everyday as you can see from the picture. We have to brush it off. And it was not there until recently.

 

[proavia]

That orange stuff is rust - from rebar being too close to the surface. The rebar is supposed to be encapsulated in the gunite and the plaster installed over the gunite. In your case, chances are the rebar was slightly exposed when the plaster was installed.

 

[eikotsai]

Hi. I just tested with the magnet and it seems to stick to it. So I think you are right! Thanks so much for solving the mystery for us. Regarding the repair, you mean we don't need to drain the water, right? We are thinking about DIY. Could you please recommend some product? Thanks so much!!

 

[proavia]

You would be better off having a professional do it. And they can better match (not perfectly) the existing plaster that needs to be removed to get to the rebar and surrounding area.

 

[eikotsai]

Understood. Thank you!

 

[Bperry]

View attachment 491439

This photo kinda looks like there’s a small crack running vertically through the spot. Maybe an optical illusion but could be something to look at with the repair tech.

 

[eikotsai]

what if we directly apply plaster patch without removing the original plaster that get to the rebar? What will happen?

I cannot find a technician/pool company that wants to patch a small spot like this, unfortunately...