Can't figure out what this is...

[Nick P]

Hi Folks,
First up, great forum and site! I've learned so much just from reading. But now I have an issue of my own and I don't know if it's algae or some type of corrosion. So I finally decided to break out my gopro and take some photos. I hope they're clear enough.
So, I've tried slamming the pool several times, always keep my chemistry balanced, even CYA in the 50 to 80 range (not great but I'm in the middle east so the sun is pretty intense). No matter what I do, even vigorous scrubbing by hand, it does not go away. The pool I think is fiberglass with a gelcoat finish, does this make sense? To make matters worse, I believe now it may have been painted as well with some heavy duty epoxy marine paint.
Please have a look at the photos and let me know. I'm thinking now to just drain it and pressure wash the whole thing and start from scratch.
Thanks,
Nick

 

[pooldv]

Welcome to TFP!

Try some Vit C to see if it removes the stain. More here on how to do that, Pool School - Stains in Your Pool

 

[Nick P]

OK cool, thanks. I'll give that a try and report back.

 

[duraleigh]

Pool School - Metals in the Water and Metal Stains

 

[kadavis]

Cobalt Spotting - Solve My Pool Problems, try thishttp://www.poolstore.com/cobalt-cure-stain-remover-for-fiberglass-and-acrylic-pools-and-spas

 

[JamesW]

Looks like it’s a tiled pool that was painted. Tile is the only thing that will give those squares.

I don’t know what the spots are.

 

[Marlahoutex]

Why would anyone paint a tiled pool?? Hope you can solve your issue! I'm no help but am interested in what's under that paint!

 

[JamesW]

Maybe they didn't like the color of the tile?

Perhaps they wanted plain white but the tile was dark.

 

[kimkats]

In to watch and learn from this one. Once you do the vit. c test let us know what happens.

Kim

 

[Nick P]

Thanks everyone for the input. So I got home tonight and grabbed one of my 500mg vit-c supplement tablets, put it in the pool right on top of one of the stains. I was amazed. Within a minute the stain was 90% gone, plus an inch or two around the tablet was a nice bright blue.
Looking a bit closer, I see this is definitely a fiberglass pool and I don't believe now that it was painted. Even though the surface is bubbling, the bubbles are hard as the surrounding area and scraping it just gouges the surface. Reading some more on this forum and following suggestions from some responding here, it could be a cobalt staining issue. Just now need to try and track down the appropriate products to help resolve the issue.

 

[kimkats]

I would LOVE to see a pic or 10 of the whole pool and area. Fiberglass with that pattern? Sounds interesting!

Have you read what you need to get to clear it up or do you need to be pointed in the right direction? We are here to help you out if needed.

Kim

 

[Nick P]

Sure, I'll try to get some pics later this week. Too dark now for any good ones. I'm still working on the right solution at the moment. I'll have to call the local pool store and see what they have to offer and work with the products they have. Getting anything pool related here in Abu Dhabi is very difficult!

 

[kimkats]

Ascorbic Treatment to rid Pool of metal stains

See if this helps. Can you find anything like this there? It does not have to be a "pool product". That is the beauty of TFP!

Kim

 

[Nick P]

Ok thanks, I will try and find the absorbic acid.

- - - Updated - - -

It will be difficult as well, but I'll try.

 

[JamesW]

How do you get that tile pattern with fiberglass?

 

[duraleigh]

If the stains responded to vitamin C, it is surely not cobalt. Please reread this excerpt from the link provided...

Iron
In the vast majority of pools metal staining comes from iron. Iron is fairly common in well water but rare in municipal water. If you suspect a stain is caused by iron try the Vitamin C test. Place 15 to 20 Vitamin C tablets in a sock and crush them. Hold the sock on the stain for 3 to 5 minutes. If the stain vanishes or lightens then it is iron.

You can remove iron stains with ascorbic acid (Vit C). See this article, Ascorbic Treatment to rid Pool of metal stains, for directions on how.

If iron has precipitated into the water, turning it orange, brown, yellow or green, it is sometimes possible to filter out the iron particulates using polyfill pillow stuffing material. Polyfill can be used by stuffing it in a skimmer basket or making a separate bucket filter filled with polyfill and circulating water through it, replace it often.

If your fill water has iron then consider trucking in iron-free water to fill the pool. Also consider capturing rain water or diverting gutters to the pool as an iron-free source of water for replacing evaporation and water loss.

Please treat your pool for iron stains with ascorbic acid. It's pretty easy to find online but I don't know if anyone in the US will ship to you.

 

[Nick P]

Ok Thanks. That's my plan, to stick with the ascorbic acid treatment. I'm sure I'll either find it locally or find someone to ship it. I still have a few days to wait though as my chlorine levels are still at shock level.

 

[domct203]

Cobalt Spotting - Solve My Pool Problems, try thishttp://www.poolstore.com/cobalt-cure-stain-remover-for-fiberglass-and-acrylic-pools-and-spas

Be cautious with the recommendations on that website. They recommend a FC of 5% of CYA (5ppm FC to 100ppm CYA) to battle algae, and large additions of cal-hypo with no warning that excessive calcium will lead to CSI issues and scale.

They also state that green murky water is a filtration issue, and recommend a complete drain & refill.

None of that is necessary, and frankly, quite wasteful.

We do not advocate mixing pool care methods, as that will usually end with frustration.

As already mentioned, this is iron staining as it reacts to AA.