Concrete pool - Black spots (Maybe Algae) ??? Need Help

[FormerBromineUser]

It depends on your tested CYA level. See: http://poolsolutions.com/gd/best-gue...e-chart.html#a
Read it and focus then on the Best Guess Chart.

I know you have a K- 2006 and have been around the block. So you must know that if your CYA is in the high end of the range, bump the shock level FC accordingly.

If you need help, report your CYA. We will be happy to help with mor specific recommendations!

Best wishes

[Wraypau]

I took out my 2800 psi pressure washer, put on the 15 degree tip, and pressure washed the walls. (yes, the pool was still full of water, so you just hold the tip about 1 inch fro wall) and it blew all the black algae off the wall and out of the cracks, then I shocked the hell out of the pool for about a week, and man o man, it made a huge difference.

[FormerBromineUser]

Excellent to hear!!! Woot!!!!

PoolDoc always warned that black algae is very difficult to eradicate in a plaster pool. Keep an eye out for any recurrence.