Black cobweb like dirt on bottom of salt water pool

[Nikki2077]

Hello all,

I have an in-ground salt water pool, 20x40 and I have to admit that due to school and working full time all summer I didn't have the time to tend to it daily like I should have. For the last part of the summer I've had to vaccum daily but about an hour after vacuuming the dirt like stuff would re-appear, so I'm really fed up right now. I want to close the pool for the winter but I need to make sure this is taken care of before I do it. First off, this guy that works for a pool company was unable to identify what it is. The thinks it's dirt. He claims it's not black algae but I don't think he knows what he is talking about. When I vacuum it, it disappears into fine mist. Is this black algae? Please help because i'm extremely frustrated! I've vacummed with both a pool blaster which is separate from the filter and I've also vacuumed through the filter/skimmer thru waste.

Thanks

 

[Butterfly]

Black algae is rare in vinyl pools. Also, you cannot vac it up! BA is bad and requires scrubbing just to knock off the head to allow chlorine inside to start the kill.

I suggest you check your sand filter. You may need to do a deep cleaning, if you have not done one recently: http://www.troublefreepool.com/threads/73192-Deep-Cleaning-a-Sand-Filter

You should also do an OCLT to help rule out/in organics as the problem: http://www.troublefreepool.com/content/136-perform-the-overnight-fc-chlorine-loss-test-oclt

 

[duraleigh]

Thorough advice always starts with a complete set of test results. Can you post those?

Like Butterfly, I don't think it is black algae.