Weird Stains on liner...algae?

[Jeff Lebowski]

Greetings all,

My pool liner has a dozen stains which weren't there 6 months ago. I have picked at them with my finger, and can feel no difference from the non-stained areas. They are a mid green color and are grouped at three sites.

My pool water has remained mostly crystal clear the three years I have owned it. My water checks fine. There is only occasional minor tree debris on the bottom and the vacuum is on constantly.

No little kids with dirty feet, etc.

Any ideas of what they are, how to clean them and prevent more?

 

[Patrick_B]

So these are big or small spots? And nothing happens to them when you rub them with your finger, or brush them? When you say the water checks fine, what are your numbers looking like, and can you post the results?

 

[Jeff Lebowski]

Small spots, about the size of a cigarette butt. Medium green in color. Nothing happens when you rub them with a finger. I have not tried a brush.

FAC 3
TAC 3
Salt 2900
CH 150
CYA 70
TA 60
PH 7.6
Pho 200

Thanks.

(Sorry bout the lag. Had to leave the country for a spell)

 

[Catanzaro]

Small spots, about the size of a cigarette butt. Medium green in color. Nothing happens when you rub them with a finger. I have not tried a brush.

FAC 3
TAC 3
Salt 2900
CH 150
CYA 70
TA 60
PH 7.6
Pho 200

Thanks.

(Sorry bout the lag. Had to leave the country for a spell)

Q: How you are testing and where did you obtain these results? Do you have one of the recommended test kits?
Q: Liner pools have galvanized walls behind them. Some pool companies use foam to protect liners from rust if there is a tear. Do you know what type of construction you have?
Q: You have a SWG & have your levels ever been off? PH?
Q: Do you use any alternative sources (Algaecides, clarifiers, etc.)

I would suggest you have pool water tested for metals. I doubt these are all tears in the liner. I had a cut so small that you could not see it from the surface (Just the stain it produced) above the cut. Wall with chlorine was creating this. I diligently go underwater every few days (day time and night time) to make sure there are no cuts or tears in the liner. This probably occurred during constructions where the liner became weak in that area. Patched up very easily.

I you can get to a spot without diving in, possibly lean over in the pool with goggles just so you can see clearly underwater, try rubbing a spot with Vitamin C (not too much pressure) back and forth. This may remove the spots. It could be staining from many different things. I have small nuts from a tree that if it sits on the white steps for more than a day, a stain appears. Vitamin C quickly removes the stain.