Light Area Vinyl Liner Need Help

[aterri]

Hi
I need some help and I am going crazy trying to figure this out.

I have a 30,000L I ground vinyl pool. The pool is 1 year old.

This summer we had issues balancing the pool chemicals so we went to the store to have the water checked. We had low chlorine levels a Low ph around 6.

The store gave us 4 KG of alka+ which is used to increase the alkalinity and the ph. When putting it in the pool the ph and alkalinity was normal levels.

He then gave me 3 bags of pool shock. HTH Extra Super Shock (454g). I normally put the shocks at the water return jets and keep the pump running.

After putting the pool shock I had my water tested. The free chorine went to 25 ppm. The day was 43 Celsius, the following day it was still at 19 PPM, so I emptied 2 feet of water and added the water back and it was still at 14 PPM. I then proceeded to get a choline our solution that got rid of all the chlorine.

I am back to normal levels between 2 and 3 ppm.

I noticed now that I have a white section in my pool liner. I am confused, when touching the liner it is rough and bumpy. There is no way for me to get the white spot off.

Is this a chemical burn or calcium buildup?
Did I damage my liner?
What tests can I do to ensure I did not damage my liner?
Having a high free chlorine close to 30 ppm for 2 days did it damage the rest of the liner ?

No one ever mentioned to me that I should dissolve the pool shock in a bucket of water before.

Thanks,

 

[5odaw1s]

Did you dissolve the shock in some water before adding it to the pool or did you add it directly to the pool at that return outlet?
How deep is the water there?

Opps...I Missed in your post that you didn’t pre-dissolve the shock. If you let it sit on the liner and didn’t brush it or disburse in some other way, it has likely bleached that area of the liner.

 

[aterri]

The area where it is faded is 3.5 feet deep.
I did not dissolve the shock before.
Did I damage my liner or is it cosmetic?
Why is the area that is lightened rough?

 

[5odaw1s]

Cosmetic. The shock faded the print on the vinyl.

 

[5odaw1s]

And welcome to TFP

 

[aterri]

Can an oxidizer do the same effect on a liner?

 

[thetekgeek]

It appears as though you have been a victim of the pool store. Since you are here, I'd like to suggest that you read the ABC's of Pool Water Chemistry - ABC's of Pool Water Chemistry - Trouble Free Pool

Also, consider reviewing the entire Pool School E-Book - Table of Contents - Trouble Free Pool

After reading through this information and getting a good test kit - See Test Kits Compared - Trouble Free Pool - You will be armed to take control of your pool and not have to deal with bad advice again.

 

[5odaw1s]

What do you mean by oxidizer?

 

[aterri]

Are we sure it is not a calcium deposit?
Can an oxidizer granular damage the liner?
Why is the liner rougher where it is lighter?

 

[mknauss]

Welcome to the forum!
Can you tell us the chemical content of the products you used?
The alka+, was that baking soda?
The Extra Super Shock - was that cal hypo?
Is the area of concern where you added the shock?

I assume you have no real test kit as you are in Canada. That is a detriment to properly managing your pool water chemistry.

 

[5odaw1s]

There really isn’t any way to speak to the calcium deposit question without knowing what your water chemistry is. But given that the area appeared after adding the shock to that area, I’m pretty confident that the hyper chlorite granules bleached the liner there.
And yes, any granular oxidizer/sanitizer with chlorine, calcium hypochlorite, Dichlor, etc will bleach a liner if it sits in one spot long enough. Even liquid chlorine will if it’s just pored in the pool and not disbursed by brushing the area or very slowly pouring it in front of a return. I dilute my liquid chlorine in a bucket of water, then slowly pour it in front of a return line in the 8.5 foot deep end.
I don’t know why the liner is rough at that spot. Maybe somebody with that kind of knowledge can chime in on that.

 

[jblizzle]

It appears that the HTH Extra Super-terrific Awesome Amazing Shock is cal-hypo.

Did you add it and the baking soda at the same time?

What do you mean by rough? Like sand paper? Or like wrinkled?

 

[aterri]

Like sand paper. Feels like rocks are under. I feel some wrinkles too.

Baking soda was done 4 hours before. The ph was stable before adding the shock.

The pool was overshocked.

 

[jblizzle]

Was the baking soda mixed in or did it just settle on the bottom?

If baking soda just sat on the bottom with poor circulation, then it could have a local very high pH. If the cal-hypo was then added into this same area, the local high pH could interact with the calcium to create local calcium scaling.

 

[5odaw1s]

If it feels like little pebbles under the liner, that sounds like impurities in the base under the liner.
In my area most pool builders use a mixture of Portland cement and sand as a base that goes over the dirt. Sometimes there are small clumps, like really small pebbles, of Portland cement that don’t get completely broken up.
When the sand is mixed with this and troweled onto the dirt, it looks very smooth. But when the weight of the water is added the sand and cement powder around the little clumps depresses, but the clumps don’t. They end up feeling like little bumps under the vinyl.

I don’t believe over shocking the pool hurt the liner.
Depending on CYA levels, some pools require chlorine levels above 30ppm during aSLAM.

 

[aterri]

So at the end of the day why is the liner lighter in that section? It is only visible in the shade. Is it calcium?

 

[jblizzle]

It depends. We can't answer that given the information you provided.

Either the dye has been faded, or you have a build-up on the liner.

 

[mknauss]

If it was calcium, you should be able to rub it off with a fingernail or some other blunt device.

If it is wrinkled and faded, that is from the cal hypo sitting on it and damaging the liner.

Sadly, you cannot provide us any test data to provide better guidance.

 

[aterri]

Which test data?
When you say damaged is it cosmetic damages or the liner needs to be replaced?

 

[jblizzle]

Either way it would only likely be cosmetic.

You never did explain how the chemicals were added. Did they both sit on the bottom?