mustard algae

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

mustard algae

Postby kahleds » Sun 02 May, 2010 14:09

Having mustard algae problems in my pool. Any tips would be greatly appreciated. Pool chemistry is as follows:

FC 2.5
CC 0
pH 7.4
25000 gallons


chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2381
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

mustard algae

Postby chem geek » Sun 02 May, 2010 16:11

Cyanuric Acid (CYA) level?

Read the Pool School including the section on Defeating Algae and then maintain an appropriate FC level for your CYA level.
kahleds

mustard algae

Postby kahleds » Mon 03 May, 2010 09:43

CYA level is 45.
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2381
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

mustard algae

Postby chem geek » Mon 03 May, 2010 10:49

Mustard algae is harder to kill so would require shocking to around 27 ppm FC and getting behind light niches and ladders (if present) and putting in poles and other equipment used in the pool. After you get rid of it, make sure you don't let the FC get below around 3.5 ppm. If you don't get rid of it all, then it might take double that FC level or nearly 7 ppm to keep it away, but hopefully you'll kill it the first time so that you won't need this higher chlorine level. You'll want to keep the shock level for at least one day beyond when you'd normally stop -- so one day beyond 1) the pool is crystal clear, 2) you measure <= 0.5 ppm CC, 3) you have <= 1 ppm FC drop overnight.

You could alternatively use a sodium bromide algaecide (Yellow Out, etc.) since that gets around CYA to kill yellow/mustard algae, but will leave you with a partial bromine pool for a time (a few weeks to a month or so) with possibly higher chlorine demand (see this link for more info).

I assume your readings are coming from a good test kit, such as the Taylor K-2006, and not from test strips. If they are from test strips, then they are worthless. If they are from a pool store, they may also be worthless. Invest in a good test kit. You can get the Taylor K-2006 here or the TF-100 here with the difference between these kits described here.
Guest

mustard algae

Postby Guest » Mon 03 May, 2010 11:39

Thanks for the information!

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