Yellow/Brown dusty deposits that reappear repeatedly

[matt4x4]

Wayne, this stuff we're talking about is DEFINITELY a type of Algae, it starts like deposits in spots, if left unattended, it gets to be more and more, what you don't really notice (until you start to vacuum) is that the whole floor will get a thin layer on it - it's so even that you think your remaining liner is spotless, however, turn the vac on and see the color difference. The walls also get it - more on the walls with shade and relatively hard to see.

[matt4x4]

That's it, when your pool water starts to look that aqua blue/green milky look, you're finally killing it off, another 3 days of filtering with the DE and you should be clean.
PIAlgae is what it SHOULD be called!

[chem geek]

I've had my cl levels at about 30 for 3 days now. pump on 24 hours/day.

Pool is definately clearing up.

An FC of 30 with a CYA of 40 (that you mentioned in an earlier post) is a disinfecting chlorine (HOCl) level of around 1.3 ppm (an FC of 25 is an HOCl level of around 0.8 ppm) so it looks like we are narrowing down the amount of chlorine needed to kill this stuff to be a minimum of at least the column of 1 ppm in this table. If others have this problem with different levels of CYA (especially higher), then we can confirm this and eventually update Ben's Best Guess CYA chart to have at least two shock columns -- one for plain green algae (probably a 0.3 ppm level) and another for this mustard/yellow algae (probably a 1 ppm level). That leaves black algae where others have written about rubbing Tri-Chlor pucks on the algae, but I'm not sure about what overall pool chlorine levels are used at the same time to be effective.

Thank you all for keeping track of your chlorine (FC) and CYA levels during your battles with this algae. I know that the chemistry of what's going on is the last thing to enter your minds, but this information will ultimately help others.

Richard

[Wayne LaBanca]

OK, looks like were getting some good analysis going here. I'm not arguing that is not algae, I just think it's stil questionable. Maybe what I had/have is not the same thing. Does anyone know of a type of algae that just settles rather than attach? This is very interesting, maybe we are on to ta new strain???

Wayne