Are the stains from metal or algae?

[tfrailey]

Stains are green, blotchy, smooth to the touch. I have super-chlorinated twice to 30 ppm and brushed. They were not there when I closed my pool last fall, but they were there this spring when I opened it. I assumed they were algae since the water was very green as usual. I used a Nature 2 last season but did not replace the cartridge this year after reading about it. What is the best way to tell if the stains might be from metal rather than algae?

[Watermom]

Rub a Vitamin C tablet on the stain and see if it removes it. If it does, it is most likely a metals issue.

[tfrailey]

Thanks Watermom. I don't have any in the house, so I'll have to pick some up and try that. I don't suppose I can substitute an over 50 multivitamin, lol?

[BigDave]

Yikes! No! You already suspect a metals problem - don't put "Silver" in.

[tfrailey]

Haha Big Dave - thanks for the tip! OK, I tried the vitamin C tablet, rubbing on the same green spot until it was worn down to my fingers - didn't seem to have any affect.

[tfrailey]

Just an end of summer followup to this thread. I maintained the pool water at 5 - 10 ppm FC and CYA at 60 and the stains gradually went away. I am assuming the stains were algae and just stubborn because they faded away in a few weeks and are now gone.