Brown stains spreading

[mbar]

Your chlorine is not too high. According to the "best guess chart" that we use, with the cya 70, your chlorine at 12ppm is good, a little high but as you can see it doesn't even come near shock level. You can run your pool at about 8ppms.

Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

All of your numbers seem to be in range, but you didn't post your calcium levels.

As for the stains, I would try putting in a sequestering agent first - something like sequasol, or jack's magic, or metal free. Put in enough per the directions on the bottle. A little extra won't hurt, but not enough will keep some metals free to precipitate out of the water. Keeping your ph low, 7.2 is ok, but no higher. Let your pump run 24/7 for a while and see if the stains get any lighter. If they don't let me know. Then you can do a regular stain treatment. As for where did the metals come from? I don't know, but since they are in there you need something like the sequestering agent to keep them in suspension.

[gregugadawg]

take a water sample to your local pool store and tell them you need stain remover. Be sure you use a metal remover when you add the stain remover as well. This is going to work since the vitamin c worked on the stains. You will however need to lower the chlorine level to less than 1 before treating the stains.

[waterbear]

I would say Marie is right on the money. She is pretty much the expert on stain treatment around here

Brown stains are usually caused by iron. Might be intersting to get your water checked but then again, once the stain has formed the metal is no longer IN the water, unless it is a recurring problem such as your fill water.