Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.


Postby buzz00 » Sun 31 Aug, 2008 10:49

Been fighting this stuff for a wile now.Thought it might be dust or pollen but I now know it is algae.It looks like a brownish dust on the bottom of the pool.Wave your hand at it and its gone only to come back in a day.I took a pimpet and sucked some up and put in in a jar.In the jar I can shake it up and it looks like pea soup(GREEN),but it doesn't stay in the water colume after 30min or so It all settles back to the bottom.
I,ve shocked for 4 days at 25 to 30ppm FC with all equipment in the water and brushed as well as I could.It took 40 bottles of bleach!It came back in a week.
I have been a faithful follower of BBB but am getting tired of poring bottle after bottle of bleach in my pool,pluse I don't have alot of money.
I am thinking of going to the dark side!Algaeside that is!
Is polyquat 60 the best stuff?
What about that Aquachem Algaeside 50 stuff at wally world?

chem geek
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Postby chem geek » Sun 31 Aug, 2008 12:04

If this stuff tends to grow on the shady side of the pool, then this sounds like yellow/mustard algae. If it's all over, then it's more likely to be dirt or pollen.

If you take some of it in a jar in the shade and cover it with a breathable fabric/cloth, then does it grow in the jar? Also, can you feel any of it -- is it gritty like dirt, squishy like pollen, or slimy like algae? Do you have a microscope and can you look at it -- if it's round and solid looking possibly with spikes, then it's pollen, but if it's somewhat transluscent and more oblong, then it's algae.

Yellow/mustard algae takes higher levels of chlorine to get rid of -- the shock level is an FC that is 60% of the CYA level and you have to soak equipment and get behind light niches, etc. If you don't completely get rid of it, then to keep it from coming back requires an FC of 15% of the CYA level. Use of PolyQuat 60 algaecide will help let you use a lower chlorine level (for maintenance, not for shocking) and use of a phosphate remover will also work but will need reapplication. Another preventative approach is to have 50 ppm Borates in the water, but I've seen less experience of this reported on pool forums regarding yellow/mustard algae (it does seem to prevent green algae even in high phosphate level pools).

You can also try using a skimmer sock to collect some of it if you stir it up.

The AquaChem Algaecide 40 MSDS (I couldn't find 50) is here and is an inexpensive standard linear quat. It is better to use PolyQuat as it is more effective, longer lasting, and doesn't foam.


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