Using a Nature 2 system with the BBB method

[tdkorson]

I am documented red-green color blind, so forget what I said about green stain. I just asked my wife to describe the stain color and she says it is yellow with a slight brownish tint.

[PoolDoc]

At the water line -- pollen, dirt, lotion, metals are common causes.

At the bottom -- mustard algae.

Brush, chlorinate . . . and scrub the water line with a baking soda paste on a sponge. If that doesn't touch it, hold a vitamin C tab against the stain. If THAT removes it, it's metal based.

[tdkorson]

Vitamin C does the trick. Rubbing tablets on the stains just above the current water line got them all off, but the stains at and just below the water line and on the fiberglass steps remain. So it looks like I should try an ascorbic acid treatment.

Question. My fc is down to 0, ta is about 100 and CYA is 65, but my PH is 8.2 Should I lower the Ph a bit before using the ascorbic acid? Any advice about about the best sequestering agent to use?

[rcy100]

If I'm not mistaken, ascorbic acid will lower your PH, but I don't know by how much, so maybe get the PH closer to where it should be before treatment? Since your FC is 0 and will stay there for the AA treatment, you may want to add algaecide (not copper based) to the pool. After the AA removes the stains, you want to introduce chlorine slowly or the stains will redeposit on your pool.

If you don't want these stains to return.... 1. GET RID OF THE NATURE 2 2. Don't let your PH get as high as it apparently has been (8.2 you posted). PH tends to drift up with a SWG...keeping total alkalinity at 80 will slow the PH rise. It worked for me. Also adding 50ppm of borates will dramatically slow the PH rise. MY pool has locked in at 7.6 since dropping TA to 80 and adding borates. 3. GET RID OF THE NATURE 2