Killing black algae while pool is drained.

[Phillbo]

Hello, I have spots of black algae in some of the rough areas around the walls and on the steps.

I plan to do a drain and refill soon for a few different reason and would also like to attack the algae while it's empty. I plan to drain the pool and then hit the algae with chlorine using a pump up sprayer. I think I'll do this a couple times over a few days and then let it dry out for a coupe weeks.

Does this sound like a good approach to killing it? Or will it just grow back once I fill it back up?

Any suggestions are appreciated.

In ground Plaster pool.

I live in Az so not concerned with the pool floating while empty. It sat empty for 4 months when I first purchased the house with no issues.

I also plan to disassemble the filter and spray the grids with bleach and let them completely dry out as well.

[Phillbo]

No opinions on this approach to rid my pool of the black algae?

[chem geek]

With black algae, the key is to scrape off the waxy surface layer with a wire brush to expose the roots of the algae underneath to high chlorine levels. Technically, you could do this without draining and just maintain a high chlorine level in the pool, but again the key is REGULAR brushing to scrape off the surface layers once or twice a day.