Black algae in empty pool

[tark101]

We have drained our (Plaster) pool and have small patches of Black algae that just wont go away!!! I can scrub and get some of it, but not all of it.



What would be a good way to get rid of this stuff!!!

[waste]

You could try pouring straight bleach on it, then scrubbung. If the bleach could puddle on the area it would be more effective. Black algae has a 'waxy' outer coating that helps protect the colony from the bleach's killing power, brushing opens the colony to the bleach. This won't be a one time deal, but should lessen the time and scrubbing required to kill it.

[PopcornGirl]

What about using a cream-bleach cleaner like Soft Scrub with bleach? It's thick so it would adhere longer to the surface. And if you scrubbed with a strong brush immediately after applying it, you could really work it into the "stain."
I realize that it's not ideal to add "cleaners" and their various chemical to your pool, but if you used just a little and wiped up the excess, I'd think the rest would be so diluted that it couldn't hurt.
Of course, I'm no expert so I would wait to see what everyone else thinks about this idea!

[waste]

PopcornGirl, don't sell yourself short! While in a filled pool, the foamy detergents in such a product would 'mess with' the water, in an empty pool it could be applied and rinsed off and removed before the pool was refilled.
Speaking of which, Tark are you making sure that the pool won't float while empty - it's thaw and rain time and it would be a bad thing to read a post from you asking 'what to do about a floated pool'! Black algae can be dealt with in a full pool much easier than dealing with a pool which has floated out of the ground. If you don't have to worry about the pool floating, try what PopcornGirl and I advised, if there is a chance of the pool floating, fill it ASAP (you may be able to treat some of the areas with bleach before the water gets up there, but if not- settle in for a HIGH chlorine pool for a while) Please look at some of the black algae posts here to see what sort of FC you need to maintain to battle this. FWIW - straight 6% bleach should be 60,000 ppm (hope I got the math right ) and that should be more than enough to kill anything (if it stays in contact long enough)

[matt4x4]

There are several newer algae and mold killers available - most at the home depot, have you tried pure bleach dabbed on them?