Green pool after a foot of rain

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
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My Pool: In ground, 25,000 gallon, ozone, cartridge filters, black pebble tech
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Green pool after a foot of rain

Postby Lilmoose » Sun 02 Oct, 2011 09:54

I have a 25000 gallon in ground pool using a cartridge filtration, with ozone. We got about a foot of rain in a 6 day span. Water started to turn green, shocked, still green, added 18# of alkalinity plus to raise alkalinity
And it is still green, any thoughts

Using aqua check strips readings are:
Ph 7.4-7.6
free chlorine 5
Alkalinity 80
Stabilizer 100


chem geek
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Green pool after a foot of rain

Postby chem geek » Sun 02 Oct, 2011 23:29

Test strips are notoriously inaccurate. Your CYA level may be even higher than 100 ppm. You should get yourself a proper test kit, either the Taylor K-2006 or the TFTestkits TF-100. I'm not sure how you did your shocking, but I strongly suspect you didn't use nearly enough chlorine to keep the FC level nearly high enough. It would probably be better to dilute your pool water with fresh fill water to lower the CYA level since it will take less chlorine to kill the algae and to maintain. It is the active chlorine level proportional to the FC/CYA ratio that determines whether algae can be killed by chlorine faster than it grows. Read Defeating Algae.

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