Black Algae prevention

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
garyying
Pool Newbie
Pool Newbie
Posts: 2
Joined: Fri 11 Mar, 2016 04:07
My Pool: Gunite concrete rectangular swimming pool.
12 x 28.

Black Algae prevention

Postby garyying » Fri 11 Mar, 2016 04:24

In my house we have gunite concrete swimming pool which is awesome but the problem is during spring and summer time, when the algae attack in the pool starts and next thing you know we have to go for shocking the algae off. Which really is frustrating when it happens almost all the time. I went through web and found some article and one really got my attention about black algae in swimming pools . As I was reading through I found out that it is not necessary that, by increasing the chlorine concentration wouldn’t remove the algae completely because of the multi layer structure of algae . I really don’t have much knowledge about algae in pools. It would be great if anyone could explain how to prevent them before the spring and summer seasons are on.


chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Re: Black Algae prevention

Postby chem geek » Fri 11 Mar, 2016 14:07

You may have poor circulation at the bottom of the pool because if you are maintaining a Free Chlorine (FC) level that is at least 7.5% of the Cyanuric Acid (CYA) level then that is enough to prevent both green and black algae growth regardless of algae nutrient (phosphate and nitrate) level. For black algae that is already present, you want to use a strong brush to scrape off the head and expose it to chlorine. You can elevate the chlorine level to accelerate this kill rate.

Note that if you are using Trichlor tabs/pucks, that for every 10 ppm FC that they add, they also increase CYA by 6 ppm. So it doesn't take long for the CYA to climb which lowers the active chlorine level such that algae can then grow faster than chlorine can kill it. Though you could raise the FC to keep the FC/CYA ratio constant, eventually you'll need to do a partial drain/refill to lower the CYA level. Using chlorinating liquid or bleach avoids this problem of CYA buildup.
Greys0n
Pool Enthusiast
Pool Enthusiast
Posts: 10
Joined: Mon 14 Mar, 2016 06:38

Re: Black Algae prevention

Postby Greys0n » Tue 15 Mar, 2016 05:39

It will reapeat or you will move your pool
CharlotteEhle
Pool Newbie
Pool Newbie
Posts: 8
Joined: Thu 04 Feb, 2016 01:28

Re: Black Algae prevention

Postby CharlotteEhle » Mon 18 Apr, 2016 07:47

I think there's some problem with your water treatment system in your pool. Its not pushing the used water out completely and that promotes algae formation. You should contact pool maintenance agency in your area, they could guide you with this.

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