Black Algae Attack

[thomearl]

I think i have black algae in my spa. Lots of little raised hard black spots on the plaster. They’ve noticeably increased in amount in the last two weeks. My spa overflows to my pool, but the black spots are only in the spa. Black algae? They dont come off easily, ive been able to remove a few with a putty knife. Time to brush and slam I’m guessing?

 

[kadavis]

This might be the right time to have a chlorine tablet handy, I would take a tablet and work it into each spot. By removing the waxy cover and getting the chlorine into the algae you will have better results when you slam. Also pull light out and work around the niche

 

[thomearl]

Will do. Thanks.