Yellow/Brown dusty deposits that reappear repeatedly

[matt4x4]

I found some pics and descriptions of algae, and in turn, have to say that it may well be "Mustard algae" and not quite this brown algae i read about the other day. Mustard algae is one of those algaes that becomes resisitive to levels of chlorine up to 5ppm very quickly and may need levels as high as 30ppm to effectively kill it according to several articles i found - also, lots of brushing is required to fully expose it to the chlorine. Since this seems to be common when the swimming load dies off, your water is being mixed up much less, allowing this algae to take hold easier and quickly become resisitive to your typical sanitary chlorine levels.
I am still trying to find some sort of reference that may connect brown and mustard algae - from their descriptions, it may well be the same thing, just different terminology from different sources.....

Another couple of comments about mustard algae I found:

Yellow-green algae or xanthophytes are an important group of heterokont algae. Most live in freshwater, but some are found in marine and soil habitats. They vary from single-celled flagellates to simple colonial and filamentous forms. Unlike other heterokonts, their chloroplasts do not contain fucoxanthin, which accounts for their lighter colour. They appear to be the closest relatives of the brown algae.

YELLOW ALGAE: A wall clinging variety, also called mustard algae, is usually found on the shady side of the pool. It is sheet forming, and can be difficult to eradicate completely. Once begun, a pool owner could spend the entire season fighting yellow algae; reinfection is common. This variety is resistant to normal chlorine levels and must be dealt with firmly. Hit it hard!


Yellow Algae Phaeophyta: (Also called Mustard Algae), It creates a slimy layer that guards it from sanitizers. When brushed, yellow algae is removed easily but returns quickly. Yellow Algae can set in on any pool or spa. Chlorine may slow its growth, but will not completely kill this strain of Algae. An algaecide must be used to effectively kill and prevent this Algae.


Yellow algae is sometimes called mustard algae and appears on the pool surfaces as a fine dust. Typically it is seen first on surfaces that don't receive direct sunlight. This algae is easy to brush off, but it frequently returns. Most pool experts agree that this type is the most difficult algae to control. Use Sustain Algae Destroyer according to label directions and thoroughly brush the pool surfaces. Cleaning the filter and other equipment is especially important in controlling Yellow Algae. Circulate continuously and back-wash the filter/clean the element as needed to maintain good circulation. When the problem is under control, backwash the filter/clean the element regardless of the back-pressure/flow rate. This will rid the pool and equipment of any algae that may remain trapped in the filter.


Yellow Algae - This grown on the walls and when using your nylon brush it will dust up into a cloud. This is distinguishing between the two types.

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Brush your pool surface with nylon brush.
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Add a pound of granular shock per 10,000 gal. At the same time put in several capfuls of yellow treat. (There are several brands on the market, yellow out, yellow treat etc.)
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Circulate for half an hour then shut pool filter off for 23 hours.
Brush again before turning filter back on.
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After filter has run for 24 hours CLEAN YOUR FILTER. (If you don't clean your filter, then the algae will re-infect your pool water and you will have to start all over again!).
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Use a good non-metal based algaecide and this will help prevent yellow algae.
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After using any kind of yellow out, yellow treat etc., be sure and do new test reading of your chemicals and readjust as needed



NOTE!!! - Above statements NOT entirely true - high concentrations of Chlorine WILL kill it off without the need of other chems - algaecide may help stop it from returning.





attached is a pic of what I found, if those steps are white and this stuff has set in good - like my pool year one, then this is definitely it.
Here's another link to a small pic and description that matches our issues.
http://www.poolgear.com/algae.html (am NOT pushing anything they sell, just here for the pic!)


OK, OK, That's enough now!! I gotta do some work!

cya!