Plaster stains

[kajuntwin]

I have several stains on my plaster. They come and go but really have been there for about 6 months or so.
I checked the forum and tried the vitamin c and trichlor test.
Both did not lighten the stain.
They become lighter during sunny day and more prominent earlier or later in day.
I do have an oak tree near the pool however I never let any leaves or other drift stay in pool very long.

I should also note that my PH did get above 8.0 on couple of occasions when I was out of town.
So, not sure if I should begin shock treatment or absorbic acid treatment?

Here are my numbers;
FC 8
PH 7.7
TA 110
CH 320
CYA 40

Here are a few pics.
Thanks for any help.

 

[frustratedpoolmom]

I think you may be dealing with tannin stains. AA won't help. What did you do with the trichlor, when you tested with it? If you can give a bit more detail on how you tried it out, maybe we can suggest your next steps.

 

[Melt In The Sun]

How about acorns? I agree that they look like tannin stains, which chlorine will remove. The fact that they come and go also sound like tannins.

 

[257WbyMag]

I get those from my wax myrtles dropping crud into the pool. Run your FC at 1 or 2 ppm higher than you usually do and the stains will be gone in no time.

 

[kajuntwin]

I placed tricolor puck on top of stain for 45 minutes.
Same for vitamin c tablets.
I do have an oak tree nearby but acorns never stay in pool.
I always get them out.
By the way I have been running FC around 5-9 for month now.
Doing nothing to stains.
Might mention that ph got over 8 couple of times when I was out of town.
What is tannin stain????

 

[frustratedpoolmom]

tannin is organic...the trichlor should have done something.
Did the vitamin c change the appearance in any way, like darken the spot?

 

[kajuntwin]

The vitamin c did really nothing.
However should note that they were the small caplets vitamin c.
should i have used something else?

 

[PoolGuyNJ]

Those are not iron stains. They are acorn stains. They will fade over time.

Scott

 

[frustratedpoolmom]

I'm inclined to agree with Scott. I was asking about the vit c because if it was copper the stain might get darker.
I would go ahead and try to keep the chlorine slightly elevated by 2-3 ppm more than normal and then see if they begin to fade.

 

[kajuntwin]

Thanks for the info.
They do fade big time during the day and more prominent during dusk.
Should I use pool calculator to find shock limit and keep C that high??
I am at 9 right now and will keep it that high, brush and keep going.
Should I use any type algae treatment now?
Since with BBB I have not used any algae treatment for around a year.