Fiberglass Pool Staining

[NewFGOwner]

Hello Everyone,

This is my third year owning a fiberglass salt water pool. I noticed I have what looks like staining around the pool. It’s around all of the walls and doesn’t seem green or black. More like a shadow of the dark blue color of the pool. I’m guessing this is staining from chemicals or fading from the sun. Is this a common issue? How do I confirm if it is indeed a stain or something else. Then how do I remove?

Thanks!

 

[Texas Splash]

Welcome to TFP! The stain? ... hard to know without more info. Let's do this:
1 - Post a full set of water test results; hopefully from a TF-100 or Taylor K-2006C
2 - Post a pic or two of the effected area(s)
3 - Tell us how you normally chlorinate
4 - Do you use/add pool store chemicals? If so, what?
5 - In your part of PA, are you on a well?

 

[NewFGOwner]

My chlorine has been maintained between 2.5 and 4 currently. PH is 7.8, but constantly going to 8. Alkalinity 99, CYA 60. I have a salt water generator that normally had the chlorine higher at around 5. And higher in previous years. The generator broke so while I am waiting for the replacement covered under warranty I am using chlorine granules that I put in the deep end daily in AM. My pool is 7500 gallons so this has worked fine. I use bioguard chlorine granular for this-2 oz a day. It’s been two weeks of this. I use bioguard for the ph reducer and alkalinity increaser as well. Not sure when I noticed these marks. Almost look like water marks a shade darker than the pool.

 

[NewFGOwner]

And I have public water. My calcium was low earlier in season but at over 100 now.

 

[Texas Splash]

So let me ask you this ..... the pics seem to be looked at in one of two ways .... either you are seeing a new darker area, ...... or ........ the darker area is your normal gelcoat color and instead the others areas are turning lighter. Would you say it's the latter? Some of the gelcoat is turning lighter? One way to know for sure is to drop the water level slightly below the normal water line to see if it looks chalky.

 

[NewFGOwner]

So let me ask you this ..... the pics seem to be looked at in one of two ways .... either you are seeing a new darker area, ...... or ........ the darker area is your normal gelcoat color and instead the others areas are turning lighter. Would you say it's the latter? Some of the gelcoat is turning lighter? One way to know for sure is to drop the water level slightly below the normal water line to see if it looks chalky.

That’s an interesting point and quite possible. When you say chalky, how do I identify that?

 

[Texas Splash]

Well, probably best to share my story with you and let you decide fro yourself:

Fiberglass Discoloration (Faded & Chalky) - My Story

DISCLAIMER The following is a dialog of my own personal experience. Any processes used, chemically or otherwise, were performed strictly on my own without any recommendations from Trouble Free Pools. FUTURE POSTING I am trying to keep this thread streamlined with just my own progress for all...

www.troublefreepool.com

 

[NewFGOwner]

Well, probably best to share my story with you and let you decide fro yourself:

Fiberglass Discoloration (Faded & Chalky) - My Story

DISCLAIMER The following is a dialog of my own personal experience. Any processes used, chemically or otherwise, were performed strictly on my own without any recommendations from Trouble Free Pools. FUTURE POSTING I am trying to keep this thread streamlined with just my own progress for all...

www.troublefreepool.com

[/QUOTE

Well, probably best to share my story with you and let you decide fro yourself:

Fiberglass Discoloration (Faded & Chalky) - My Story

DISCLAIMER The following is a dialog of my own personal experience. Any processes used, chemically or otherwise, were performed strictly on my own without any recommendations from Trouble Free Pools. FUTURE POSTING I am trying to keep this thread streamlined with just my own progress for all...

www.troublefreepool.com

[/QUOTE
Fascinating, so in a nut shell doesn’t look like algae, caused by water chemistry, and corrected mechanically by sanding? Is this a cosmetic only problem? Or is their real corrosion to be concerned about?

 

[Texas Splash]

In my scenario it's strictly cosmetic on the shell. The sanding I did helped to give us some of the color back we liked and darken the overall appearance of the pool. My point though is you have to be careful about knowing your pool's chemistry history and of course using a proper test kit to see if what you are experiencing is a form of oxidation, scale, or perhaps a gelcoat defect. The water tests and spot tests will help with that.

 

[NewFGOwner]

Thank you! Very helpful.

 

[NewFGOwner]

Hello All,

I received different information from pool stores and the internet about low calcium. My calcium was at 70 at onset of summer. I raised it to over 100. I’m told by one pool company that low calcium isn’t as much as a concern for Fiberglass. That the problem with corrosion is more applicable to plaster. What are the opinions on that at TFP?? Thank you!

 

[Rhinopkc]

I have had a fiberglass pool for about 12 years, and the best things I have done is get rid of the salt water, and run my pool on liquid chlorine. You don’t need any calcium in your water, you can run your TA lower than the plaster pool guy, and just about everything that you read or hear from the guy in the pool store is going to be geared toward a plaster pool, and it’s going to be wrong. The TFP recommendations for fiberglass pools in the TFP app are pretty close to what I run, and my pool is much better than when I had the SWG. That thing was a money pit and a maintenance nightmare.

 

[Texas Splash]

I received different information from pool stores and the internet about low calcium.

That is because they either don't understand pool chemistry, or simply refuse to modify antiquated guidance. Also understand that some of those generic chemical levels were established for the casual pool owner who they expect to use chlorine tabs (pucks) which are acidic and can lower pH and TA. So some sites promote a higher CH to compensate. But yes, much of that is also geared towards a plaster pool.

Since FG pools are not made with calcium anymore, we don't worry about erosion like plaster. But a minimum level of CH seems to help provide the buffering agent required to help prevent staining. Thea's the main reason we have a minimum CH recommendation here at TFP.

 

[NewFGOwner]

That is because they either don't understand pool chemistry, or simply refuse to modify antiquated guidance. Also understand that some of those generic chemical levels were established for the casual pool owner who they expect to use chlorine tabs (pucks) which are acidic and can lower pH and TA. So some sites promote a higher CH to compensate. But yes, much of that is also geared towards a plaster pool.

Since FG pools are not made with calcium anymore, we don't worry about erosion like plaster. But a minimum level of CH seems to help provide the buffering agent required to help prevent staining. Thea's the main reason we have a minimum CH recommendation here at TFP.

Thank you! What is the minimum recommendation for CH for a fiberglass pool? I’m at about 100 right now.

 

[Texas Splash]

What is the minimum recommendation for CH for a fiberglass pool? I’m at about 100 right now.

TFP lists it as 220.

What Are My Ideal Pool Levels?

Use our tool to find ideal chemical levels for any swimming pool. Check TFP recommended levels on pH, free chlorine, cyanuric acid, and more.

www.troublefreepool.com