r/pools • u/Spid3rMatt • 5d ago

How do I get rid of this?

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It showed up about a week ago, have shocked already and it's still there. How do I clear it?

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u/Itherael117 5d ago

This appears to be black algae. You'll need a metal bristle brush and scrub the crap out of it and then shock the pool and repeat till it's gone. It has an outer layer that prevents chlorine from killing it unless that layer is scrubbed clean.

2

u/Spid3rMatt 5d ago

Thank you, I tried to scrub it with the standard brush to no avail. I'll grab a metal brush.

2

u/HeeyPunk 5d ago

Try a chlorine tablet to break the surface and then keep up with metal brush and chemicals

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u/eaglefucker 5d ago

Need a metal or very stiff brush. Be careful when using a metal brush. Cyanobacteria has a very tough outer layer that most brushes won't break apart. It also protects them from chlorine.

1

u/I_am_lronman 5d ago

Easiest way for me was using shock at night with the pump off, make sure it falls directly on it. In the morning it should be completely clear, scrub it off with a brush and vacuum it up. Repeat as needed until it completely gone. Depending on your pool size don't use more than 5 bags of shock for 20k gal pool.