New Fiberglass pool walls no longer smooth below water

Sep 27, 2012
4
New (installed in July) fiberglass pool (SWG) has developed a bit of roughness on the vertical surfaces from water line to bottom...but more pronounced on the shaded side of pool. Will not brush or rub smooth.
Drained water down about a foot and effected area did not turn white when dry. It's actually not visible at all, just doesn't have the glossy feel of the area above waterline.
If this is scaling, I'm puzzled as my water has very low CH and I have diligently tried to keep my pH around 7.4-5...when it hits 7.6, I add pH down. Took a sample of water to my local pool store to compare to my readings and they were fairly close:

FC 6.56 (couple of ppm's higher than I normally run it, but with less sun and usage it had crept up)
TC 6.56
TA 120
pH 7.3 (I had just add pH down few hours before)
CH 92
CYA 45
Copper 0
Iron 0
TDS 250
SI -0.7

While realizing the CH level is way below your recommended min., I've been reluctant to increase it as a consultant at Leisure Pools (mfr of the pool) said I should never have to add Calcium to a fiberglass pool. Not sure I agree as I would think there are probably other things beside the pool shell that could be damaged by Calcium deprived water? Anyway low CH shouldn't produce scaling would it?

They sold me some PoolLife "Pool Plus". Put recommended 16 oz. in Tuesday afternoon, but so far no detectable improvement.
Pool is very small Roman style roughly 12 by 16 with a 3 ft. spa-like swim-out at one end.

Thank in advance for any insight you can add.
 
Low CH would not cause scaling ... unless your pH was maybe very very high. I too wonder why the fiberglass has a higher CH recommendation closer too that off plaster unlike vinyl. Hopefully an expert will chime in.

Maybe the low CH actually pits the surface?

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 
BeautifulSwimmer said:
While realizing the CH level is way below your recommended min., I've been reluctant to increase it as a consultant at Leisure Pools (mfr of the pool) said I should never have to add Calcium to a fiberglass pool. Not sure I agree as I would think there are probably other things beside the pool shell that could be damaged by Calcium deprived water? Anyway low CH shouldn't produce scaling would it?

No, low CH will not produce scaling. I was a sceptic of the low CH basis held by TFP for sometime, but it is safe to say I have divulged the information here and on the below links and now accept the likes of Chem Geeks standpoint on the matter.

Low CH in a Fiberglass pool can to some small extent cause problems, please read this thread for more information regarding the issue: calcium-hardness-and-ph-alkalinity-t21461.html?hilit=low%20calcium%20hardness%20levels%20corrosive

and particularly this webpage for more information: http://www.wqa.org/sitelogic.cfm?ID=366

And this page for information on CH: http://www.taylortechnologies.com/Chemi ... ntentID=70

EDIT: I did not know what Pool Plus was, until I checked a website and deduce that it is a multifunctional tri-chlor tablet which includes Algaecide and/or Flocculant, this product is not needed if you maintain your pool to the TFP method, and certainly will not assist with your description of rough surfaces.

As for the roughness, does it scrape off? It sounds like algae from your description of shaded sides of the pool being more pronounced, play around with this roughness and try to ascertain if you can remove some for sampling or if it is the gel coating on the side of the pool has been diminished.

Does vigorously sweeping the side affected result in a smooth surface again? We really need more information and for continuity stick to your own results now that you have satisfied that they are correct.

Regards
Stuart
 
No, it does not rub off, even with vigorous brushing. I had even tried to see if anything would scrap off with careful use of a razorblade scraper in a small area with nothing showing up on the blade or any noticeable change in texture of the surface. Also, when I had the water lowered slightly to see what it looked like, as a said in original post, there was nothing to see. I even dipped a gloved finger in a bottle of muratic and scrubbed a small spot with no effect, but I didn't let the acid remain. Really, it's very slight, but still a duller feel to the touch than the surface above the water. I hope it's not permanent damage to the gel coat, but I'm starting to lean that way. Just hope whatever caused it has been corrected and will not continue during the months the pool is shut down and covered for winter.
 
Another question. The Leisure Pool rep recommended putting in some scale inhibitor when I close the pool. I'm reluctant on two accounts: one, still not sure what I'm feeling is scaling, and two, the BioGuard Scale Inhibitor I have sounds rather acidic (phosphoric acid and something else) and I'm worried that will through my pH out of balance just as I close things up. Any opinions?
 
You have no use for scale inhibitor. Simply close the pool per the suggested guidelines here on TFP and that will be all you need.

I have no clue what is causing the roughness......unless some earlier runaway pH event occurred but that seem incredibly remote.
 
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