Recurring metal stains

[oldogface]

Here's the cycle I've been in this year....

Notice metal stains, reduce chlorine, apply ascorbic acid treatment, shock (pool store chems) to get chlorine back up, notice metal stains, reduce chlorine, ascorbic acid, Pool store shock, etc.....

What I've done: after last AA treatment, added Jack's Purple Stuff as sequestering agent; decided pool store shock might be culprit; committed to BBB, TF Test Kit analysis, TFP "How to Shock Your Pool" methodology.... having completed shock using TFP recommended steps, this morning I notice..... STAINS! I really don't want to continue this cycle. Any ideas?

Current chemical analysis:

FC - 21 (sustained shock level...expect that to come down in sun )
CC - .5
Ph - 7.5
TA - 100 (down from 190)
CH - 410 (down from 800+)
CYA - 80
Borates - 50

Thanks!

 

[JohnT]

The sequestering agent doesn't last forever. You probably need a new dose around monthly.

 

[oldogface]

Yeah, I've actually added, per Jack's instructions, weekly....

 

[JasonLion]

Stains return if you aren't using enough sequestrant. Any time the stains return, you should increase the amount of sequestrant you use in the next cycle.

 

[oldogface]

Will the sequestrants affect any of my other readings?
Thanks!

 

[JasonLion]

Most sequestrants lower the PH when they are added, some do this more than others. Some consume chlorine for a day or two, how much varies. Once they have been in the water for a while they shouldn't affect the readings.