How to get rid of scale on pool walls ?

Total hardness and calcium hardness in pool water.
Scale, calcium buildup, hard water and scaling problems.
patrmich
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My Pool: 22 m², 30 m3, Kidney shape

How to get rid of scale on pool walls ?

Postby patrmich » Thu 09 May, 2019 09:47

Hello,

Last end of Summer, my pump made a lot of of noise.

Therefore I stopped using it in winter.

Now the water is green as expected.
So I started to empty the pool and discovered a layer of scale on the pool liner.

Would you have any suggestion on the ways to get rid of this layer ?
- either lowering the water ph
- and if yes, to what level and by what means ?
- or cleaning the pool liner
- and if yes, by what means ?

I thank you in advance for any suggestion.

Patrick


Teapot
Pool Industry Leader
Pool Industry Leader
Posts: 1007
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: How to get rid of scale on pool walls ?

Postby Teapot » Thu 09 May, 2019 12:01

You need to add acid to lower the pH, obviously there are dangers with handling acid. It will slowly soften the scale. Do not lower the pH too low, pH 6 minimum otherwise you can damage the liner it can wrinkle and shrink. It can work on local spots if you mix pH- with liquid soap as that helps it cling. Soap will mess up your water but chlorine can burn out the soap later but it will take a bit of chlorine.
patrmich
I'm new here
I'm new here
Posts: 3
Joined: Thu 09 May, 2019 09:41
My Pool: 22 m², 30 m3, Kidney shape

Re: How to get rid of scale on pool walls ?

Postby patrmich » Fri 10 May, 2019 03:30

Hello Teapot,

I thank you for your prompt and kind reply.

Yesterday I checked the water pH. It is rather high at 9.2.

Therefore, I guess that it would be difficult to decrease it to 6.

So, I decided to start to empty the pool.
As the water level goes down, the walls become visible.
So, with a mixture of 14° degree vinegar and soap, I started to scrub the walls gently, in order to impregnate the scale.
This morning, by scrubbing gently again the walls, the scale is easier to remove.

When the poll is clean, I am planning to refill it.

My filter pump does not work well. So, I am planning to replace it. But it could take some days or even a week or two.

In the meantime, I wonder what products to add to the water.
Currently in my area (south of France) the water temperature is around 12°C and the maximum daylight air temperature is at 18°C.

Would you have any suggestion of what products to add to the water ?

Once again, thank you in advance for any suggestion.

Patrick
Teapot
Pool Industry Leader
Pool Industry Leader
Posts: 1007
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: How to get rid of scale on pool walls ?

Postby Teapot » Fri 10 May, 2019 06:15

Hi Patrick,
Once you have removed the scale, you need to sanitise the water with chlorine. Cheepest way is with 20 ltr biddon of eau de Javel from a brico shed €13 ish. Please let me know the pH of the water you will refill the pool with, also the alkalinity and hardness so we can get an idea of possible issues. This will keep everything at bay whilst you source a pump, just need to manually stir the water and fish out any debris
patrmich
I'm new here
I'm new here
Posts: 3
Joined: Thu 09 May, 2019 09:41
My Pool: 22 m², 30 m3, Kidney shape

Re: How to get rid of scale on pool walls ?

Postby patrmich » Sat 11 May, 2019 05:03

Hi Teapot,

Thank you again for your reply.

When I read some comment about "eau de javel" used for pools, some drawbacks are listed such as pH increase and scale production.
In my city, the tap water hardness is supposed to be normal.

So do you think that I can add to my 30 m3 pool :
- either 20 liters of usual "eau de javel"
- or 20 liters of pool specific equivalent "eau de javel"
- or 20 liters of calcium hypochlorite
- or anything else ?

Sorry to bother you with such questions.

Thank you again in advance.

Patrick
Teapot
Pool Industry Leader
Pool Industry Leader
Posts: 1007
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: How to get rid of scale on pool walls ?

Postby Teapot » Sat 11 May, 2019 05:38

Hi Patrick,
Eau De Javel in brico sheds is, provided it's reasonably fresh (check dates) and look for brico with high turnover of product, 9.6% sodium hypochlorite, for simplicity call it 10%. 300ml of E De J will give your pool 1ppm of chlorine or near enough.

Pool shop sodium hypochlorite is stronger at about 14-15% but would generally cost 2x the price of brico shed Javel.
There is often a tiny remnant of sodium hydroxide left in the mix that could put up the pH by 0.1 so nothing to worry about. Whereas multi action galets are acidic and tend over time to lower pH and alkalinity albeit slowly. Most products like galets and shock will contain CYA stabiliser, using these too frequently will send up the CYA stabiliser level to a point where you will loose control of the pool water and algae etc will take over. CYA controls the water and not chlorine.

The biggest issue to a rising pH is over alkalinity. In plastic or vinyl pools alkalinity value is not as important as in tiled/plaster/pebbletech etc. I run my pool at around 40ppm alkalinity and haven't used any pH minus for a season, I have disconnected my pH doser. Unfortunately ignorance and misinformation are prevalent throughout the pool industry and people default to Google for basic chemical levels for pools, that information was based on the requirements for plaster/tiled pools.

The important point of running with alkalinity at 40-80ppm is your pH will remain so much more stable for our use but you would need a lot less pH- or pH+ to get it to move as the buffering is so much less.

Calcium hypochlorite is a very strong form of hypochlorite but it will increase the water hardness leading to scale formation and higher pH in some cases, fine if you have soft water.

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