mustard algae

[Guest]

i have mustard algae in my pool and i'm having a heck of a time getting rid of it.this is my first pool and i've done a pretty good job of keeping the pool nice and clear but i have this stuff in just a few spots and it's kicking my but.i went to the pool supply store and told them what i have and they sold me BioGuard Back up and i put that in yesterday around 1pm and this morning it was still there so i put in more of the back up and also shocked the crap out of the pool and the chlorine is around 5-6.long store short did they sell me the right stuff because today i was on line and BioGuard makes a product called Banish and it says it kills all algae.PLEASE HELP i have family coming over for the 4 of July.

[Guest]

Yellow algae is shock resistant. Use a product with yellow in the name, yellow out, yellowtrine, etc.

Sweep it off all surfaces and pour in the algicide. Keep the chlorine level up. Vacuum the dead stuff to waste and sweep any new growth off surfaces.

Good Luck

[Guest]

thanks for the advise

[chem geek]

Products with "yellow" in the name mostly have sodium bromide and will consume lots of chlorine to produce bromine. That does help battle yellow/mustard algae, but it is NOT true that it cannot be fought with chlorine alone. It just takes a higher shock level of chlorine. Instead of the normal shock level for green algae of 40% of the CYA level, for yellow/mustard algae it takes first lowering the pH to 7.2 and then a shock level of chlorine of 60% of the CYA level held for at least 2 days (3 is better). All pool equipment (poles, brushes, etc.) should be in the pool during the shocking and swimsuits should be cleaned in hot soapy water so as not to reintroduce the algae back into the pool.

To keep away yellow/mustard algae even if it is reintroduced, a minimum Free Chlorine (FC) level of 15% of the CYA level is required. This compares with a minimum FC level of 7.5% of the CYA level to keep away green algae.

I do not know if PolyQuat 60 algaecide used for weekly maintenance will keep away yellow/mustard algae (I know it will keep away green algae, even if chlorine is absent).

[Guest]

I went back the other day where they sold me the BackUp and they apologized for selling me that.The lady that sold it to me had been working there for two days and thought she was giving me the right stuff but they took back the BackUp and gave me Banish and after 1 day its gone.Thanks for all the advise.

[chem geek]

Actually, BioGuard Back Up is mostly "Alkyl dimethylbenzylammonium chloride" as seen in this MSDS link so is a standard linear quat (not as good as PolyQuat 60 and it can foam, but is similar) that is normally used to prevent algae, not to kill existing algae. BioGuard ALGAE Banish is mostly metallic copper (and copper sulfate) as seen in this MSDS link and is a general algaecide (it's also quite acidic so lowers the pH). However, having copper in your pool means that if you get the pH up for whatever reason, you can precipitate metal (green or blue-green or dark) on pool surfaces and blonds in your pool may get green hair.

So I'm glad it got rid of your algae. If your pool ever turns green, remember that you've got copper in it and need to lower the pH and/or use a metal sequestrant.