Please Help! Is this Black Algae on my Vinyl Pool Liner??

hardwareguy

Active member
Jul 28, 2007
41
Wabash, IN
Our liner is 3 years old and this has developed in the past year. I noticed that it was happening, but it did not appear to be getting any worse. It in only happening on one side of the pool, the south side in this case. As noted in my sig, I have a SWG and Auto Cover. I have not had the installer of the pool come over to the house, but thought that maybe some of the Guru's would have any idea. If I rub the area, it removes the liner color. Additionally, none of this is happening below the water line, only directly above.

[attachment=0:1li7ofw8]DSC_0496 [640x480].JPG[/attachment:1li7ofw8]

What stumps me is the fact that it is happening only on this side of the pool.

Any help and thoughts are appreciated!!

Brian
 

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dmanb2b

TFP Expert
LifeTime Supporter
Apr 4, 2009
3,734
NY
I hate to say this and it's a pure guess on my part, but that seems to be a defect in the liner print (above water surface). Rubbing your liner with a nylon brush or magic eraser should not pull print off of it. Sounds like that area get some good sun exposure and it has made the print brittle...if that's possible?

It may pay to have the PB come out if it is still under warranty.

Hopefully some folks with more experience here will chime in quickly

In the mean time...could you post a full set of test results...just in case it is some sort of algae.
 

hardwareguy

Active member
Jul 28, 2007
41
Wabash, IN
I should have also stated and is not that obvious from the pics, that the spots are black. Test results:

FC--4.5
CC--0.0
PH--7.6
TA--140
CYA--70
CH--240
Salt--3400
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
That is certainly not black algae. From the photo it looks like a defective liner, though I suppose it might have something to do with the cover perhaps rubbing against that area when it is opened or closed.

Your numbers look fairly good, nothing that suggests anything about the marks on the liner. I would lower TA a bit, but that wouldn't affect the liner or algae at all.