Fiberglass pool -- Waterline stains

[SpykeYs]

Hi,

I have just completed an ascorbic acid treatment to get rid of my iron stains. I have raised water as much as possible and the treatment so far is successful. That being said, I still have a waterline stain which I tried to remove with magic eraser to no success. The stain is light but you can definitely see a line all round the pool at water line level. Assuming it's not IRON has I just did a AA treatment, what do you suggest to remove the waterline stain ?

Would acid muratic do the trick ?

Thanks,

 

[Texas Splash]

Can you post a pic or two of this waterline discoloration?

 

[SpykeYs]

Can you post a pic or two of this waterline discoloration?

See attached.

Prior to AA, all the fiberglass was yellowish with a yellowish water line. All if that is gone now.

Thanks.

 

[Texas Splash]

So that light gray color above the waterline is what you are referring to correct? About 3-4 inches or so? Have you tried rubbing a test area with a Vitamin C tablet to see if it's the same iron product as what was removed below from the AA treatment?

 

[SpykeYs]

Yes, this is correct. I have tried and Vitamin C tablet will not remove or fade away.

 

[Texas Splash]

Interesting. I wonder if that exposed portion of the shell/gelcoat has simply oxidized a bit over time. Two things you could try come to mind:
1 - Try rubbing a chlorine tablet on a test area (keep it moving though) or sprinkle some cal-hypo powder on a test area. Perhaps that dingy color is more of an organic substance that has settled into the pores of the gelcoat.
2 - Check around for a polishing compound that you can use to buff the areas. If a polishing compound doesn't work, a rubbing compound may be required. You could also check with any local Marine shops as I'm sure they deal with gelcoat polishes as well.

Curious to know if any of these things work, or something else perhaps.

 

[Texas Splash]

@SpykeYs, just to confirm. I deleted the post above as requested, but the rest of the thread is still active about your waterline. Do you still want this thread active? Delete it, or perhaps combine with your other thread below?

Recurring Iron Stain -- Looking for permanent solution

Hi, I recently (3 years ago) bought a new house with a 16x25 fiberglass pool (10 000 gallons) and I am having recurring Iron Stains issue which comes back at least once or twice every season. It covers the entire submerged fiberglass which becomes yellowish. Before I start my acid ascorbic...

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