Black Algae Stains

[dwyerst]

I have a friend who has a pebble tech pool that has significant black algae stains.

We have tried water blasting them off (the pool is still full) but it is very tough. have also tried brushing but it is really not making a dent.

Any ideas?

 

[JasonLion]

Getting black algae completely killed is not at all easy. One approach that works for some people is to go up to mustard algae shock level and then pressure wash the pool surface (under water). Some care is required. You need to get the nozzle close enough to the surface to remove the algae, but not so close that it damages the surface.