Staining from water fill?

[Macpool11]

The staining didn’t appear immediately. The pool builder treated it as iron, since it has a slight yellow tint around it, but it appeared around a month after being filled. Nothing really seems to lighten it, and I am now wondering if it is from when the pool was filled. Check out the hose position in the photo, the stain fans out toward the drain. The photos are from different angle, the photo of the stain is looking down from deep end, and the one with hose is looking from shallow end toward deep end.

Is this likely? With the stain not showing right away? It also might be worth noting that this area where the hose is, was wet almost constantly during plaster install. They had a pump in this area to control water. Although it was pretty dry the day they polished/filled. What effect would this have on the plaster here? Plaster in this case is hydrazzo.

 

[Texas Splash]

Perhaps we can ask @onBalance for some expert thoughts on this one?

 

[onBalance]

I am not seeing any yellow color at all.
Is the darker gray color surrounding the one main drain the discoloration that you are concern about? That is a very unusual discoloration. Not absolutely sure what occurred. But it does seem like a running pump could have been possibly involved with creating this discoloration.

My suggestion is to drain the pool and power-sand that dark area. That is your best chance to remove it properly.
I highly discourage any acid treatment program. I doubt it will remove the graying color, but if is does, it will result in an etched and rough surface that will stain easier and faster than would be normal in the coming months. Of course, one can drain and power-sand and make it smooth again after an acid treatment etches the plaster surface.

 

[Macpool11]

I am not seeing any yellow color at all.
Is the darker gray color surrounding the one main drain the discoloration that you are concern about? That is a very unusual discoloration. Not absolutely sure what occurred. But it does seem like a running pump could have been possibly involved with creating this discoloration.

My suggestion is to drain the pool and power-sand that dark area. That is your best chance to remove it properly.
I highly discourage any acid treatment program. I doubt it will remove the graying color, but if is does, it will result in an etched and rough surface that will stain easier and faster than would be normal in the coming months. Of course, one can drain and power-sand and make it smooth again after an acid treatment etches the plaster surface.

thanks for the response. You’re right, it doesn’t look yellow to me either. I was told that it looks yellowish up close.

Yes, the darker gray area around the drain is the stain in question. I was told yesterday that the pump was only there to remove water and acid and water after they were done with plaster. The stain lines up with where the hose was located while filling the pool. It’s not always as dark as the photo, it depends on the time of day. In full sun, it is faintly visible, but in overcast conditions or early morning, it is very apparent. I showed the photos to the supervisor and he was pretty quick to offer solutions. They will be out next week to work on it.

 

[onBalance]

If it is only a stain from iron, copper, or dirt, then it will be easy to remove with a stain treatment of some kind.
But if the plaster is discolored, then that may be more difficult to remove.
FYI, some submersible pumps spray out some water while pumping. That is what may have occurred. But perhaps, the fill hose is what caused this.