What is this, please?

[Andrewp]

I have been struggling to get control of the pH in my pool that is tiled with marble and has a large, 4 m overflow to a gutter below. I have been adding HCl every few days to keep it within range, but I am wondering if the large exposure to oxygen from the overflow might be increasing the pH.
Also, after purchasing a Dolphin robot vacuum, I found the white residue in the photo below. I had the water tested, and it was found to be low in calcium chloride, which I have since added 18kg. A subsequent test found that I need to add 4kg more. Could the white residue be from degradation of the tiles or grout as it seeks the CaCl2 that it was/is lacking? The tiles have also gotten quite rough, they are no longer smooth like they were originally.

 

[Mdragger88]

Yes, aeration from a spillover can increase ph.
While we wait for input from others about your white debris,
Can you post a full set of test results?
Fc
Cc
Ph
Ta
Ch
Cya
Salt
Borates (if used)
Water temp

 

[Andrewp]

Yes, aeration from a spillover can increase ph.
While we wait for input from others about your white debris,
Can you post a full set of test results?
Fc
Cc
Ph
Ta
Ch
Cya
Salt
Borates (if used)
Water temp

Below is the last one, but I question its accuracy, I know that the salt is not correct, at least!

 

[Mdragger88]

Do you have a way to get a proper test kit that includes all the tests I mentioned above?
See Test Kits Compared &

Pool Test Kits - Further Reading

www.troublefreepool.com

Also, They are showing total hardness which includes calcium hardness as well as other things. Its really imperative that you have accurate measurements to adequately care for your pool.
Until then you can do your best to adhere to the recommendations here

What Are My Ideal Pool Levels?

Use our tool to find ideal chemical levels for any swimming pool. Check TFP recommended levels on pH, free chlorine, cyanuric acid, and more.

www.troublefreepool.com

 

[ajw22]

We cannot give advice based on the posted pool store test.

Alkalinity cannot be zero with a pH of 7.1. A CYA of 5 is unmeasurable. Copper of 0.4 ppm is enough to stain the pool and turn blonde hair green. You say salt is incorrect. All the measurements are questionable.

If you are able to adopt TFP methods, we can advise you.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

Your tile residue may be one of these problems...

Calcium Scale - Further Reading

www.troublefreepool.com

Efflorescence - Further Reading

www.troublefreepool.com

Waterline Scale Removal - Further Reading

www.troublefreepool.com

 

[Andrewp]

Here is the initial test from a different company that seems more accurate. I did add the CaCl2 and baking soda and then requested a new test from the second company. It was delayed because they were calibrating their equipment, they said. Then when I got it back, I disputed the results, so they did it again, which resulted in the one with the impossible, low salt reading.
One problem is that not everything is available here, so I will have to look into how to get one of your recommended test kits sent here.
The one question I would like answered now, if possible, is should I keep adding CaCl2, especially if I already have calcium scale? How can I tell if something has been added to the tile to make it rough, or taken away? I’ve taken a stainless steel brush to it and have not been able to get anything off. Another is whether or not having marble tiles is part of the problem?
Thanks for your help!

 

[Andrewp]

We cannot give advice based on the posted pool store test.

Alkalinity cannot be zero with a pH of 7.1. A CYA of 5 is unmeasurable. Copper of 0.4 ppm is enough to stain the pool and turn blonde hair green. You say salt is incorrect. All the measurements are questionable.

If you are able to adopt TFP methods, we can advise you.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

Your tile residue may be one of these problems...

Calcium Scale - Further Reading

www.troublefreepool.com

Efflorescence - Further Reading

www.troublefreepool.com

Waterline Scale Removal - Further Reading

www.troublefreepool.com

I did the acid test for Calcium Scale and it did fizzle. Does it make sense that I could have calcium scale and still be low in CaCl2?