Black stains in vinyl pool

[dhuston]

I have several black stains in the deep end of my pool. They are smudge/blotchy like in appearance. They range from a grayish to almost black. They were new this spring.
I have tried brushing with a nylon brush and also with a sponge with a scratchy surface on one side. Neither of these work.

The chemistry is good.

Any ideas would be helpful

 

[pooldv]

Welcome to TFP!

Most likely they are organic stains. You can rub a trichlor puck on one to see if it lightens the stain. If it does then elevate FC up toward shock level for your CYA, [FC/CYA][/FC/CYA], and brush daily. It should go away in a week or two.

 

[dhuston]

OK
Will give that a try.
thanks.. will let you know the results

 

[dhuston]

I placed a trichlor puck on the stain and it removed it. I have moved the puck over the other stains and they have disappeared. I left the puck on the stain area for half an hour or so. I also elevated the FC to close to shock levels to help.
Thanks I believe this is the solution.