Mustard Algae?

Eauclaire

Well-known member
May 28, 2015
58
Quebec, QC
You can inhibit photosynthesis by laying down a black garbage bag over the stain and keeping it weighed down to completely exclude light for a week or two. The ’reeky’ smell you describe is DMSO (dimethyl sulfoxide) which can only originate biologically. But minerals may have nucleated on the biological material resulting in mineral deposits.
 

Auburn02

Well-known member
Oct 8, 2019
265
Mobile, AL
Am I taking too simple an approach here by asking what does the area feel like? If it's biological/algae/etc shouldn't it have a fuzzy or slimy or slick texture? If the plaster is stained shouldn't it feel just like the unstained plaster next to it? So what does the area feel like to the touch?
 
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FlaPoolGuy

Gold Supporter
Oct 5, 2019
104
Florida
It does look like something settled in the spot and you have a localized stain. Other possibility/question: how is the paint holding up? I'm wondering if that particular area has a lack of paint/is something bleeding through? Was the pool brown before being painted and that's the actual, original color showing in one spot where the paint is gone/worn off?

Is that spot rough or smooth?
 

reggiehammond

Gold Supporter
Oct 4, 2020
375
Fort Worth, Texas
Pool Size
30000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-60 Plus
I’d just like to double back to your previous comment about the pool service levels being good according to the service. They’re not, based on that Leslie’s testing (which is likely wrong in some way too). The FC is not in line with the FC/CYA chart. At a CYA of 60, minimum FC is 5.
 

Shawkr

Member
Sep 9, 2021
22
California
Am I taking too simple an approach here by asking what does the area feel like? If it's biological/algae/etc shouldn't it have a fuzzy or slimy or slick texture? If the plaster is stained shouldn't it feel just like the unstained plaster next to it? So what does the area feel like to the touch?
It feels just as the rest of the pool does just maybe a little less ‘smooth.’ There is definitely not a slimy/algae texture to it!
 

Shawkr

Member
Sep 9, 2021
22
California
It does look like something settled in the spot and you have a localized stain. Other possibility/question: how is the paint holding up? I'm wondering if that particular area has a lack of paint/is something bleeding through? Was the pool brown before being painted and that's the actual, original color showing in one spot where the paint is gone/worn off?

Is that spot rough or smooth?
The paint is definitely aging. I think the idea was a cheap five year-ish fix, and it’s now been about seven-years. The stain feels just as the rest of the pool does just slightly (hardly noticeable) less smooth. The original pool is not this brown-ish color..
 

Shawkr

Member
Sep 9, 2021
22
California
I’d just like to double back to your previous comment about the pool service levels being good according to the service. They’re not, based on that Leslie’s testing (which is likely wrong in some way too). The FC is not in line with the FC/CYA chart. At a CYA of 60, minimum FC is 5.
Understood. I don’t have much knowledge but our new pool guy (1 month of service in) is maintaining the levels according to him.
 

Shawkr

Member
Sep 9, 2021
22
California
Does anyone know if maybe the paint is wearing, and the paint wear mixed with the fiberglass is causing this abnormal stain. My girlfriend has been diving down with her new goggles and she says it looks like fiberglass material within the stain which leads me to believe it’s simply the paint failing… Another professional came by and said the pool is due for an overhaul but the cost is $15-$20,000.
 

Shawkr

Member
Sep 9, 2021
22
California
You have a plaster pool surface not paint.

Get a 6ft piece of pvc pipe, 2 Inch

Push it down in the water over the stain with one end sticking out the water. Slowly pour a bottle of muriatic acid into the pipe so that it falls through the pipe and comes out under water over the stain. I'd pour about 20 ounces at a time. Have a second bottle on stand by.

Pour, wait a minute, move the pipe a little, lift it from the floor a few inches, pour, wait, slowly move and lift repeat.
It should take about 10 mins to empty one bottle. That stain will be gone after two bottles.
Sorry for my ignorance. I was under the impression the pool is fiberglass and my dad had literally painted (with the pool paint), the surface of the pool approximately 7 years ago. Do you still believe it’d be worthwhile to try your approach mentioned?
 

ferretbone

In The Industry
May 24, 2016
161
tx
Sorry for my ignorance. I was under the impression the pool is fiberglass and my dad had literally painted (with the pool paint), the surface of the pool approximately 7 years ago. Do you still believe it’d be worthwhile to try your approach mentioned?
No not yet.
now I'm not sure what pool you have. Rebar on one side is showing, you think its painted, and now maybe it's fiberglass.


To me I'm looking at the picture and it looks like a plaster pool with no paint or liitle to no paint. fiberglass pools can fool in pictures, but those steps say a gunite pool to me.

So I need to know if its fiberglass or gunite/plaster.

edit, it's got to be a gunite pool. Its the tile on the side real glass tile?
 
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Shawkr

Member
Sep 9, 2021
22
California
No not yet.
now I'm not sure what pool you have. Rebar on one side is showing, you think its painted, and now maybe it's fiberglass.


To me I'm looking at the picture and it looks like a plaster pool with no paint or liitle to no paint. fiberglass pools can fool in pictures, but those steps say a gunite pool to me.

So I need to know if its fiberglass or gunite/plaster.

edit, it's got to be a gunite pool. Its the tile on the side real glass tile?
It’s absolutely fiberglass with some sort of paint/plaster over the entire surface. And yes the tiles were installed around the perimeter about seven years ago when all the other work was done. We’ve been told by numerous pool companies that have stopped by that it is not rebar, however, one guy said it was.

My mom says it is 100% not gunite. It is fiberglass for sure. You can see the paint/plaster fading in many areas of the pool as well.

isnt there rebar under fiberglass?
 
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Shawkr

Member
Sep 9, 2021
22
California
It wouldn't have rebar showing in the pool if it were fiberglass.

I think you should spend your bucks fixing the finish (replaster) instead of trying to add automation.
Correct, we don’t think it is rebar after help from the forum and professionals stopping by.
What is the most cost effective way to refinish a fiberglass pool? I just found out about vinyl via googling, can you refinish a fiberglass pool with vinyl? I also saw ecofinish but it appears pretty pricey.
We’re in a tricky position because now that my dad has passed (totally unexpected) my mom is likely to move out of the home and downsize in the next maybe two years. But this stain is a major eye sore and $20,000 to re-do the pool is not in her future.
 

JamesW

TFP Expert
Mar 2, 2011
28,259
It’s absolutely fiberglass with some sort of paint/plaster over the entire surface.

My mom says it is 100% not gunite. It is fiberglass for sure.
It looks like gunite to me.

Gunite can be coated with plaster or it can be coated with fiberglass.

I really do not think that you know for sure what you have.

Have a professional see if they can tell for sure.
 

Shawkr

Member
Sep 9, 2021
22
California
It looks like gunite to me.

Gunite can be coated with plaster or it can be coated with fiberglass.

I really do not think that you know for sure what you have.

Have a professional see if they can tell for sure.
Ok so you all are referring to the structure? As in concrete vs gunite? Then fiberglass and paint/plaster over? I can look through old documents to try and find the answer. Our home was built in the 60s and the pool was originally done then with the home. Not sure if that helps but maybe the age can help determine the structure.
 

Shawkr

Member
Sep 9, 2021
22
California
It looks like gunite to me.

Gunite can be coated with plaster or it can be coated with fiberglass.

I really do not think that you know for sure what you have.

Have a professional see if they can tell for sure.
Hi James and everyone,
I looked through an appraisal from when the home was purchased in 1986. The documents state that it is an “inground gunite pool”. With that said, is it possible the pool has been surfaced with fiberglass? And then some sort of paint or plaster.
 

JamesW

TFP Expert
Mar 2, 2011
28,259
What is an affordable yet durable way to resurface the pool?
To get a good surface, it is going to cost some money.

You can invest in the renovation in hopes that the cost is offset by a higher resale value or sell it as is and let the buyer deal with it, but you will likely get less money for the house.

Some buyers want turnkey properties and don't want to deal with renovations.

Some people are looking for a project, but they expect a substantial discount.

If you're looking to sell soon, maybe consult with a local real estate agent to see what they advise.

If the house is in otherwise excellent condition, then it might be best to renovate the pool.

If the rest of the house needs extensive work, then it would probably not make sense to invest in a pool renovation.

Maybe get some renovation estimates.

The existing surface will probably need to be completely removed.
 
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Shawkr

Member
Sep 9, 2021
22
California
To get a good surface, it is going to cost some money.

You can invest in the renovation in hopes that the cost is offset by a higher resale value or sell it as is and let the buyer deal with it, but you will likely get less money for the house.

Some buyers want turnkey properties and don't want to deal with renovations.

Some people are looking for a project, but they expect a substantial discount.

If you're looking to sell soon, maybe consult with a local real estate agent to see what they advise.

If the house is in otherwise excellent condition, then it might be best to renovate the pool.

If the rest of the house needs extensive work, then it would probably not make sense to invest in a pool renovation.

Maybe get some renovation estimates.

The existing surface will probably need to be completely removed.
Understood. Thank you so much for your help James. It is much appreciated. And thank you everyone else for your help as well! I noticed we did have some muriatic acid at the house. Would putting it on the stain for the heck of it cause more problems or is it worth a try if I have time?
 

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