Liner staining

[Herwick]

Now that our water is clear we can see staining. There are 2 different ones that no amount of brushing seems to be getting rid of. The first and most troublesome, as it looks horrid, is a black ring around the pool. The second is a yellow stain on the floor of the shallow end.

FC: 8
CC: 0
PH: 7.1
TA: 97
CYA: 25

We got a lot of rain last night and had to do a partial drain this morning. Brought FC levels back up to 12 and gave my sock a few squeezes. We have been able to see the black stain for a little over a week, I think. The yellow stain we just noticed yesterday. Any ideas what they could be and how to fix them?

 

[Herwick]

Here is the yellow staining. Its a lot more noticeable in person.

And obviously the black staining.

 

[pooldv]

Here are a couple of tests you can do to see if the stains are organic or metal.

Rub a trichlor pucks on the stain for a 1-5 minutes to see if it lightens the stain. If yes then the stain is organic. Raise FC to half or a little more of a shock value and brush daily. [FC/CYA][/FC/CYA].

Rub a Vit C tablet on the stain for a few minutes up to several hours to see if it lightens the stain. If it does then the stain is metals. Pool School - Metals in the Water and Metal Stains