Dirt Stains or Algae?

[misterlunski]

Hello, periodically I will get these spots on my pool floor. One such spot has a tree over it. I am leaning dirt stains but wanted some other opinions. Thanks.

 

[PoolStored]

What happens when you brush them? If they go away, likely just organic material.

Did you fertilize your lawn? Maybe iron staining from fertilizer. If they don't brush away, put some vitamin C tablets in a sock, crush them up a bit and rub them on the spots...see if that takes care of it.

Does not look like algae, but you can always do this test to confirm. Link-->Overnight Chlorine Loss Test

 

[misterlunski]

They don't go away when I brush. I read somewhere that sometimes dirt can get calcified and it kind of locks them on to the floor? I do fertilize my lawn once a month. What would the vitamin C tablets do?

 

[PoolStored]

Place 15 to 20 Vitamin C tablets in a sock and crush them. Hold the sock on the stain for 3 to 5 minutes. If the stain vanishes or lightens then it is iron.

 

[misterlunski]

Ok so I sprinkled some cal hypo over these spots and let it sit for a few minutes. The stains came right off once I brushed it. What would this lead you to believe?

 

[PoolStored]

What would this lead you to believe?

The stains were organic, like from a seed or leaf...

 

[misterlunski]

Ok so you still don't think it was any type of algae?

 

[PoolStored]

No, I think it was organic staining.

 

[misterlunski]

Cool thank you for your help