How To: Clean Black Algae on the Cheap

It is unusual for me to do a how to on my blog. I do not know how to do much that is useful (defined here as handymanesque) other than make up descriptors like handymanesque. I have talked here about my house before. I think I may even have given a video tour of it way back. Maybe not. Maybe I will do that later this week. None of that is the point. The point here is that we have a pool and we have a neighbor with a giant tree that sheds like some kind of four letter word. It does not matter what time of year, there is always something that is coming off of that tree in an unearthly volume. I did some checking and it would seem that the source of black algae could be anything including using the same suit that has been in the ocean. Personally I will stick to blaming my neighbors tree. It is an object on which I can fixate and burn down with laser beams from my eyes. Anywho... 

My problem is two fold. First, no one wants to swim in a pool that has black spots on the side of it. Second, there is the description that I just pulled from WikiAnswers which is as follows.

Black Algae grows in small spots generally up to about 40mm in size. It grows on pool surfaces and is very difficult to remove as it forms in layers when extra chlorine is added to kill it only the top layer is effected and the rest stays as good as new. Black algae can be found in bathrooms between tiles and silicone seals, aquariums on the glass, and in the ocean. Black algae is the toughest algae to get rid of and is very resistant to chlorine.

There is also this encouraging quote from poolcenter.com on the algae page:

Perhaps the most aggravating strain of algae, it has been compared to herpes; "once you've got it, it's there for life." This is not entirely accurate, but the difficulty in eradication is due to the strong roots and protective layers over top of the black algae plant. Black algae will appear as dark black or blue/green spots, usually the size of a pencil eraser tip. Their roots extend into the plaster or tile grout, and unless the roots are destroyed completely, a new head will grow back in the same place. The heads also contain protective layers to keep cell destroying chemicals from entering the organism. Like yellow algae, black strains can bloom even in the presence of normal sanitizing levels and proper filtration. I was once told that this form of algae commonly enters a pool inside the swimsuit of a person who's recently been to the ocean.

Awesome, my pool has herpes. Now what. You would say surely other people have this problem and there is probably a professional solution that is quick and easy. Well it is out there theoretically. I tried the chemical route with this stuff over the winter. There is a specific concoction that you can get at the pool store for about $30 for 20oz. Two bottles of that stuff last fall following the directions to the letter (they failed to mention that whole bit about the roots and protective layers though) which produced a little bit of fading of the black spots but did not eliminate them. Finally, they even started to multiply again this spring when the water started to show signs of getting warmer.
So I have tried lots of things and for the most part my big purge of cleaning the pool in the spring worked. But leave it to the monsoon season to wreck your backyard with multiple storm days in a row and make your pool a bacteria and mold breeding ground while you cannot clean it.
I will post the happy ending for this saga later on, just know that I think I can beat some black algae.