Stubborn stains and what to do????

[Dameyerson]

The gunite/plaster(?) is white and it usually looks like Caribbean water. I have had a portion of this stain for three years. It didn’t get any bigger but it wouldn’t go away. Taking pictures to various local pool stores, no one could identify it. Paid one pool company to come look at it and they shrugged. I thought it was staining due to several evergreens that had grown too close to the pool. Had them cut back. This year, after opening, once the water was clear, I noticed the stains had spread significantly.

I never have a problem with clarity. The pool does go through a lot of chlorine as we have full sun exposure all day.

I found your site. Used the technique for identifying stains and as you can see from one photo, there are three puck circles in one stain, so I started the slam process.

I used the test kit that is recommended/sold through this site. My water chemistry before starting:

CYA: 40
FC: 1.2
CC: 0
TA: 100
CH: 250
PH: 7.2

This is day three of the SLAM. I have been checking three times a day, morning, afternoon and last thing at night. Each time I add chlorine, I’ve been brushing the pool. Last night the chlorine was 16. This morning, it was 10.5.

Any help would be greatly appreciated.

 

[mknauss]

Welcome to the fourm!

If your FC dropped nearly 6 ppm overnight you are killing algae or other organics. If there is any way you can test and dose more often it will go faster. Be sure to brush those stains alot during the SLAM.

Good luck.

 

[Dameyerson]

I am checking every few hours now and keeping it at 16 with minimal additions. I also bought an "algae" brush. While I'm not seeing visible signs of lightening, I am now seeing "dirt" or I guess dead algae when I push with the brush. I am brushing more often now.

 

[JamesW]

Kind of looks like copper stains. Try ascorbic acid or sulfamic acid on a spot.

Have you used any copper algaecide?

 

[Dameyerson]

I did try the ascorbic acid ... Ground vitamin C in a stocking ... In various spots. Unfortunately nothing changed. still hoping the SLAM will work ... On Day four so, we'll see. Thanks

 

[duraleigh]

It may work, but the SLAM is not intended to remove stains. Complete the SLAM as per the instructions and then start on identifying and removing stains if they still are there.....I think they will be.

 

[Dameyerson]

If the puck test shows the stains are organic wouldn't that mean that it is an algae not "stain" and hopefully the SLAM will eliminate them? What else could I be doing to eliminate organic stains?

 

[JamesW]

It looks like classic copper stains to me. The turquoise and black/gray are typical copper stain colors.

A vitamin C tab will usually make a darker spot.

Sulfamic acid might make the spots lighter. Jack's Magic Stain Solution #2 The Copper & Scale Stuff is sulfamic acid. Try some on a spot.

Note that sulfamic acid will combine with chlorine for a long time and you will get persistent CCs for weeks if you do a full treatment.

 

[Dameyerson]

My guess is I have multiple issues. Just read about Jacks Magic and it requires a specific pool chemistry. I'm still working on getting a successful overnight chlorine test. I don't think I can treat for copper till I'm done.

 

[mknauss]

Have you ever added any products with copper in them?

 

[Dameyerson]

Not that I'm aware of. I'm not new to pools ... 7 year owner now, but up till this issue, it was all smooth sailing. Could my well contain enough copper to be the issue?

 

[mknauss]

Copper is rarely in your water source. It comes from copper piping, or a heater core, or copper algaecides, or multi component solid chlorine additives (most anything for a pool with with the word 'Blue' in the name).

 

[JamesW]

Can you show a picture of the the whole pool?

 

[Dameyerson]

Too many shadows and too windy today. I'll try and take one tomorrow.

 

[Swampwoman]

Do you have a read on metals in your well water?
Eg. Maganese can also make that color of stain...but in theory I'd expect it to respond a little to ascorbic acid, whereas copper sometimes just goes darker.

Another test on the copper theory once you've completed the slam would be to try dry acid on it. If it works, its likely copper. Alternately you could use MA if you had a way to apply it, eg maybe a makeshift dish soap wand if used with caution.