Whats the black smokey looking thing in the bottom of my pool?

Question

Like My Pool is clear and blue, but at the bottom at some parts there is like this black smoke looking thing , its wierd.

Answer 1

It just might be Black Algae. Let's hope not,that is hard to get rid of,and can grow into your plaster. You better go in for a closer look.

Answer 2

Go down and take a look, but be careful to watch your back ;] smething might just get you

Answer 3

It could be brown algae.  Check your chemicals, including your alkalinity levels... get your alkalinity level in check first, then chlorine.  Simply put, if your alkalinity is too low, then your pool will have trouble using the chlorine you put in it, even if you dump a bunch in there.