Black algae or metal stain

[PoolDoc]

Only if your chlorine stays high.

Bleach raises the pH while it's present as free chlorine, but once the chlorine is 'used up', the pH effect from that individual dose of bleach disappears. Test with OTO (clear => yellow drops) purchased locally (Walmart!). If the chlorine is high (dark yellow or orange), skip chlorine doses and don't try to adjust your pH. If the chlorine is on scale with the OTO comparator (<5 ppm), go ahead and adjust your pH.

[Crazziee]

Still waiting on my test kit. Hoping it shows today.......

I am not seeing the black (algae) change color or begin to clear. Could it be that its metal related?

[PoolDoc]

To affect black algae, you have to (a) have high chlorine levels AND (b) brush the heck out of it.

[Crazziee]

Okay, I will up my brushing

=======================================

someone needs to invent a power brush with a spinning head, Would make my life easier...

[Watermom]

Look at the bright side ---- you will build up your muscles brushing!

[PoolDoc]

Keep in mind, we haven't established that any of those spots ARE black algae. The most definitive test is to scrape some off with your fingernail, and smear it on a white card: black algae will smear dark green.

Brushing will make plaster wear through spots WORSE!

But, if you DO have black algae, a brush like this

Pentair R111616 604A Algae Brush with SS Bristles, 6-Inch

will help.



NOTE TO OTHER READERS: Do *NOT* use a metal bristle brush on fiberglass or vinyl pools, EVER!