I have some brown spots that have turned out to be the flagstone chipping off and landing in the pool. If these chips stay on the pool surface for more than 4-5 days, they leave a brown spot for some reason. I poured Muriatic acid on one and let it sit for about 2 minutes and it made it go away. I poured muriatic acid on another but not long enough and it turned grey but did not completely go away. You need to find out what it is. Bird poop, things falling off the trees, etc. What is it? What color is your coping?

Have you fertilized your yard lately? If fertilizer gets in the pool and the pump is off, it can sit on the bottom and cause spotting.

I have regular concrete coping and plain blue tile. We haven't fertilized at all, but we have had high winds off and on. I've had bark that has sat on my pool for a few hours.

Ok, so you suspect it may be bark? Is there anything?

I don't know??? I'm just guessing, but I really don't think so.
They start out light gray and just get darker until they are a brown color.
They can't be scrubbed off, Algaecide doesn't work and Ascorbic Acid doesn't work. I'm stumped. My pb is sending the Pebble Tec Installation company out next week to look at it. The Pebble Tec guy called me this morning. He is very curious. He says he has no clue, but might know once he sees it.

Well it looks like its darker blue around that dot/stain in the picture...isn't it?

I really don't think it's algae or you would have been able to brush it off with the wire brush. It might pop back up again, but you would at least be able to remove it temporarily. I wonder if it's a contaminant that got inside the PT as it was being applied and is now staining it from the inside out. It's really odd, it sounds like you've done all the right things to get rid of it!

I think I've done all I can. The Installer hopefully will know more. Adam's Pool Solutions in San Jose did it and they have a really good reputation. Hopefully he can diagnose it and fix it. My pool builder seems to think Adams will take care of it.

Barco,

Yes, it is darker blue around it. I had applied a sock with vitamin C around that spot and another. After about 2 hours, I lifted the sock and the calcium around the spot was gone, which just made the spot look darker. I have a lot of calcium on my pool. When Adam's called me this morning to schedule an appointment, he asked me to put acid in my pool to lower the PH below 7.0, and then tonight and tomorrow, brush the calcium off. He tells me that the PH will come back up, but lowering it will loosen the calcium off of the walls and floor and get it off before he comes out and he can get a better look at what's underneath the calcium.

Hi there - I was just checking to see if you found out what the spots where on your pool? I hope you found out what the problem was. Have a good day!

Hi there - I was just checking to see if you found out what the spots where on your pool? I hope you found out what the problem was. Have a good day!

No, I haven't yet, but I think they must be some kind of mineral depositing and staining my pebble fina. I've been using Jack's Magic Purple Stuff, but obviously something isn't working right. The Plaster Company owner is coming out this Tuesday to take a look at it. My husband was sanding calcium off of the pool this weekend and took a closer look at the largest and darkest spot. It is not fuzzy and doesn't brush or sand off. It's an actual stain in the plaster. You can see the Pebble Fina design through the stain. At this point I have about 30 of them in my pool, but not in my spa which is attached, but higher with a waterfall. I'm not sure how they are going to approach this, but all I want is it fixed a this point. I will post again when I know what they are going to do.

Problem Solved!!! Hallelujah!!! I didn't do anything wrong!!!
The plaster company just left. Turns out that Pebble Tec is aware of this problem. I have a "south african worm". It's an organic worm that got into the Pebble Tec solution. It grows like a shell into the Pebble Tec Mixture. Over time as the Pebble Tec cures completely, it starts coming through and is visible, but it was there the whole time. Pebble Tec is really good. They are going to pay for everything. I chose to have my pool surface chipped out and re-done in October. It is safe to swim in, so we can still enjoy our pool this summer and then in October it will all be fixed. He says Pebble Tech has spent over a million dollars re-doing pools that got the bad batch across the country. Ours is the first one he's come across in his area.

Wow!! No wonder you couldn't figure out what was wrong! That is really crazy, I've never heard a story like that. Glad your mystery is finally solved!

I just had Pebble Tec's black pearl installed and it's stunning. Makes me wonder however if such spotting could be seen on my surface. I'll keep an eye out on wind free days.

Mine didn't show up right away. I've had my pool in for almost 4 months now. I started seeing these spots about 3 weeks ago. My Plaster company says that it was in a bad batch of mix from South Africa and that it's in there from the beginning and grows through the curing process which is why it can take a couple of months after installation before you start noticing them. I have the Bella Blue Pebble Fina so it's a bright color and it wasn't hard to see the dark gray spots coming up. They now look even darker and look almost orange/brown. I wonder if it's just the Fina mix that was bad. I don't remember what he said about that. I'm just so relieved that I know what it is now. My Pool Builder is going to re-do my start up for me once they re-plaster. He is going to put all of the chemicals in and maintain it again for the first 30 days to make sure it cures right(they did this the first time too), and he will put the salt in again for us. I am very happy that my plaster company, Pebble Tec and my Pool Builder has made this turn out okay for us and have gone out of their way to fix it and guarantee quality.

On a somewhat related note, you indicated that you are sanding calcium off your pool - I too have what appears to be calcium growing on the pool surface and have been brushing them off for virtually the whole summer. Do you know what it causing yours?

Also - how much purple stuff do you put in your pool? Does it help with the calcium?
Thanks.