Weird deep end stains in new fiberglass pool

Jump to latest Follow Reply
C

chazas

Gold Supporter
LifeTime Supporter
Jun 4, 2007
254
Northern Virginia
Pool Size
12200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
My pool guys literally just turned maintenance of my new white fiberglass pool over to me this week, though it has been in the ground a couple of months.

There are some weird geometric stains in the deep end that don’t come up with brushing. They almost look like something scratched it. I have been running a new Pentair Warrior SI cleaner ever couple of days, but I can’t see how anything on that would be abrasive enough to affect new gelcoat. The pool sat in my front years for a couple of weeks before it was installed this winter, with dirt and leaves ion the deep end, but this doesn’t look like something from that.

Anyone have any idea what this is?A9DE9927-F623-43D1-BFA4-BCB95790F536.jpeg
6F064EB3-26AD-4874-BF8A-4E878D89CD5B.jpeg
 
Last edited:
  • Like
Reactions: danielhaggen
Those “lines” are tree debris from an odd tree. It’s not them, it’s the fainter lines towards the middle of the deep end. More visible in the first photo.
 
The very faint squiggly lines right? Those are odd. I suspect the water is still too cold to get in there. You might try using a brush pole to hold & rub a thin sock or nylon containing a few crushed-up Vitamin C tables in it on the stain. See if that helps. If not, try the same with a chlorine tab/puck directly on the stain, but don't let the puck stay in one spot. My hope is that something organic dripped or laid in such a way that if left a temporary stain (liek tannin), but that is a really odd formation.
 
I will try both. I have another idea what it might be. We had a heavy rain last week and there were a lot of dead worms in the pool, most of them had drifted down to the deep end before I ran the robot. Could be robot worm smushage. Doesn’t answer why it doesn’t come up with a brush, but that’s the only thing the cleaner could have done I can think of.
 
  • Like
Reactions: CRAD_oz
There also was some gritty debris in the pool from some work they’d done on the concrete cantilever. If the robot scratched the pool with that, it would be a much worse answer. TBD I guess.
 
I tried the puck trick, hard to tell. The area where I left the puck might be a little bit lighter, but it also might be my imagination. I turned the SWG up just in case it’s biological. Tomorrow, the Vitamin C tablet trick.
 
  • Like
Reactions: Texas Splash

Enjoying this content?

Support TFP with a donation.

Give Support
chazas said:
No luck with the Vitamin C either, I am bummed. I have notified my pool builder.
Click to expand...
Certainly is odd. Well, let us know what your installer thinks. The only other thing I don't think you tried was dry acid (for copper) - in a sock as well. But it doesn't seem to fit that scenario. Curious to hear what you find out.
 
Consistent with what all contractors think, I'm sure it will be, "it's supposed to be like that" and I'll be fighting with them and Barrier Reef for a year, which bums me out. (I am still fighting with a high-end stove company for a replacement of a cooktop installed last July that was obviously and visually defective - I'm very stubborn, but don't like to have to to it.)

Texas Splash said:
Certainly is odd. Well, let us know what your installer thinks. The only other thing I don't think you tried was dry acid (for copper) - in a sock as well. But it doesn't seem to fit that scenario. Curious to hear what you find out.
Click to expand...
 
He tried a pool eraser on a pole - no effect. And a couple more spots have shown up, also mechanical-looking. The only thing I could possibly have done is the robot - but it's a standard Pentair-branded Maytronics. There's nothing on the bottom of it that would have scraped the pool - what touches the pool is the treads and there are two of them, not single track like the stains, and my google searches haven't turned up a single instance of a pool robot staining a pool surface.

The installer is going to reach out to Barrier Reef. TBD I guess. I'm not happy.
 
  • Like
Reactions: Texas Splash
I updated this in my build thread, sorry. The textured finish was either not applied in or at some point scraped off of these areas. I have as of yet not had a definitive response from Barrier Reef on this. My PB is following up and I am keeping on them, but TBH they are letting this and one other “fix” item slide, and I’m not particularly happy about that.
 
So, Barrier Reef came at the beginning of the season after a lot of cajoling and complaining on my part. The crew drained the pool, couldn't figure out what the staining was, but when they power washed it to look at it better to figure out how to fix it, it went away. All good, I've been happy all summer.

I went out this morning and the stain is back, in exactly the same place. I'm at a complete loss. Of course, it doesn't respond to brushing - it didn't before. Maybe I dive down with a magic eraser and try that.

This is the weirdest thing.

EDIT:

So I guess I've learned the following.

(1) It clearly has something to do with the gelcoat since the stains appeared in exactly the same place in the same weird shapes. I will report it to Barrier Reef again but I'm not expecting much.
(2) It can be removed mechanically, though draining and powerwashing a time or two a year seems extreme. Brushing and a pool eraser did nothing. I need to look into alternate methods.
(3) Something causes it to reappear over time, whether it's metal or something else in my water. I ordered Jack's Magic Stain ID kit. Maybe one of the things in there will work, though ascorbic acid did not.

Anyone else got any bright ideas?
 
Last edited:
That is very odd. The weird shapes of those stains, and that they return the exact same way> :scratch: That would appear to be a gelcoat manufacture issue. No metals or organic material is going to create the exact same stain in the same location. If this was a plaster pool, I might be concerned about metal or something leaching "up" from below, but I don't think that would be the case here.
 
Texas Splash said:
That is very odd. The weird shapes of those stains, and that they return the exact same way> :scratch: That would appear to be a gelcoat manufacture issue. No metals or organic material is going to create the exact same stain in the same location. If this was a plaster pool, I might be concerned about metal or something leaching "up" from below, but I don't think that would be the case here.
Click to expand...
I agree, odd, but I feel like running down every possibility before I go back to BR will stand me in good stead. I expect we're going to end up sometime next year in exactly the same spot, which is an offer to refinish the whole thing with Ecofinish. Still not sure I want to do that to a new (now newish) pool, if I can figure out a way of removing the stains without a full drain.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply