What's happened to my pool surface?

[DrewLG]

So this pool came with the house. As you can see from the photo of the steps, the surface finish is inconsistent -- top step is grey with streaky brown staining, next step is less so, bottom step even less. The closeup photo shows the bottom of the pool: irregularly light- and darker-blue, with small dark (almost black) spots, mostly near walls or other vertical surfaces. Brushing, even with a stainless-steel brush, doesn't affect any of this.

What has happened here, and what can I do to fix it -- especially the brown staining? Is the inconsistent/missing blue surface just due to wear? Is the staining from metal, or something else?

Some background info:

The pool had previously been maintained with trichlor tabs in a floater, cal hypo shock, and muriatic acid -- and I also found a half-empty can of Clorox XtraBlue dichlor shock, a bottle of Clorox Super Water Clarifier, and a bag of soda ash. When I moved in, water was clear but pH was low (6.6) and CYA was sky high at around 200. Water costs 5 cents/gallon here, but I gritted my teeth and exchanged enough to bring the CYA down to 50.

Now I'm maintaining the pool with liquid chlorine (in an automatic feeder) and muriatic acid only. Water is clear. My Taylor reagents are old so I'm waiting for a TF-100 kit to arrive later this week, but FWIW, the Taylor readings do match what I get from LaMotte test strips:

• FC: 5 ppm
• CC: 0
• pH: 7.6
• TA: 100 ppm
• CH: 500 ppm
• CYA: 50 ppm

Any ideas?

 

[YippeeSkippy]

That looks like copper staining to moi.... and you mention that dratted Clorox XtraBlu stuff, so it makes sense.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

Copper in Pool Water - Further Reading

www.troublefreepool.com

Maddie

 

[Oly]

If your pool is not leaking that is good news. Your pool surface has probably experienced years of abuse including metal staining and chemical imbalance resulting in plaster damage. Eventually your surface will need to be chipped out and replastered. For now I would recommend an Overnight Chlorine Loss Test when your new reagents arrive, to determine if the black spots are algae and if so develop a plan to gear up for a SLAM Process. If your water is clean then follow the FC/CYA Levels balance your CSI, learn to live with your exotic plaster finish and save for a replaster.

 

[DrewLG]

That looks like copper staining to moi....

Thanks, Maddie, those links were super helpful. Tomorrow I'll see whether topical dry acid lifts the staining.

If your pool is not leaking that is good news. .... learn to live with your exotic plaster finish and save for a replaster.

No leaks. And thank you -- I closed my eyes, took a deep breath, and thought, "Exotic, exotic, exotic." Opened my eyes and the pool didn't look quite so bad anymore.

 

[Noreaster]

Is this area smooth, or is it pitted? The brownish area in the middle of this pic looks like a pit that goes to the gunite. The different colors look like layers of plaster or possibly paint. The first pool i had - there were a bunch of those pits that i though were just stains. Ended up having to refinish the pool.

If its smooth and just discolored, ignore my above assessment.

 

[DrewLG]

Is this area smooth, or is it pitted? The brownish area in the middle of this pic looks like a pit that goes to the gunite. The different colors look like layers of plaster or possibly paint.

It's smooth -- or rather, it's equally rough everywhere. It's not what I would call pitted.

But you said paint. Is that common in gunite pools? Because I've been thinking that this is plaster, but what I'm seeing -- the fading, the complete absence of color on some surfaces, etc. -- does seem more consistent with some sort of paint.

 

[IceShadow]

My understanding is that it was more common back before environmental regulations restricted what the paint could have in it, and the paint actually held to the surface underwater. These days some still paint, but it never seems to last because the paint doesn't hold as well without all the environmentally damaging materials in it.