Black stain on tile grout

Jump to latest Follow Reply
G

gjpe

0
Jul 26, 2012
17
Hoping someone can help. Fiberglass pool with SWG and waterline tile. Pool is about 3 years old. The side that is full shade has black stains starting to appear in the grout. I have tried chlorine in a spray bottle with a brush. No luck. I have tried soft scrub and a brush. No luck. Lastly I tried a stain remover granular product in a sock that you scrub against the tiles. No luck.

The black strain will not rub off with my fingernail and almost seems to be "in" the grout.

It exists below the waterline, at the waterline and above the water line.

Any ideas on how to remove? Is it unsafe in any way?
 

Attachments

  • image.jpg
    image.jpg
    80.2 KB · Views: 66
It may be black algae. It usually appears on the pool surface as isolated black spots, dark circular patterns, or blotchy black patches. Black algae typically afflicts plaster pool surfaces and tile grout since they are somewhat porous. It is virtually impossible on vinyl or fiberglass surfaces due to the smooth surface that prevent the roots from embedding themselves. Take a look at some sample pics here: Black Algae

Since you stated that you cannot get it to come off with your fingernail, try using a butter knife, or similar dull implement, and gently scrape a small sample of the stain and then smudge it on plain white paper. If the smudge is a greenish color, then it’s black algae. Please perform that test and report back with the results.
 
BoDarville said:
It may be black algae. It usually appears on the pool surface as isolated black spots, dark circular patterns, or blotchy black patches. Black algae typically afflicts plaster pool surfaces and tile grout since they are somewhat porous. It is virtually impossible on vinyl or fiberglass surfaces due to the smooth surface that prevent the roots from embedding themselves. Take a look at some sample pics here: Black Algae

Since you stated that you cannot get it to come off with your fingernail, try using a butter knife, or similar dull implement, and gently scrape a small sample of the stain and then smudge it on plain white paper. If the smudge is a greenish color, then it’s black algae. Please perform that test and report back with the results.
Click to expand...

Thanks! Will do that first thing tomorrow morning and will report back.
 
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