What are these marks, can I clean and prevent

[dedee]

In a couple of places on our terrace these white stains have appeared. Can this be easily cleaned without damaging the non slip porcelain tiles.
The marks have the appearance of the type of calcium type build up from hard water. We have never put tap water on the terrace.

Any advice gratefully received..

thanks

Andy

edit the whole terrace can been seen here

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[Dan]

I want to say efflorescence but it appears to be running down the surface of the tiles to me. Which efflorescence wouldn't do I don't think.

Have you tried a cleaner first to see what that can get off?

Can you test a tiny area with something that could scratch the surface a tiny bit to see if it's just on the surface of the tiles?

 

[dedee]

Hi Dan, thanks for you reply.
I had not heard of efflorescence before. Having googled it I think that it is the problem. I tried a little 10% acidity white vinegar and I can see the residue bubbling away, just like in the kettle. Attached is a photo after a little cleaning with said vinegar and a view of the grout showing distinct white deposits.
The tiles were laid on a schluter drainage mat and hence it is seeping out of the schluter bara rak edging.
I guess there is little I can do to stop it.

When searching efflorescence a product called ZIDO cropped up. Are you familiar with this or any other cleaning product that you could recommend as i understand that vinegar could possibly damage the tiles.

Many thanks



Image of grout on horizontal

Original stain after 10% vinegar

 

[Dan]

Oh it's efflorescence for sure then.

So the salts in the products used work their way to the surface then pool up.

So washing often will help. Then just deal with the pools of it which will be in the same place all the time.

 

[dedee]

Oh it's efflorescence for sure then.

So the salts in the products used work their way to the surface then pool up.

So washing often will help. Then just deal with the pools of it which will be in the same place all the time.

Oh it's efflorescence for sure then.

So the salts in the products used work their way to the surface then pool up.

So washing often will help. Then just deal with the pools of it which will be in the same place all the time.

Thanks again Dan,
Are you able to recommend a suitable cleaner?
I read that phosphoric acid (toilet limescale remover) should do the job without damaging the tiles but I would welome an expert opinion.
Thanks

 

[Lou]

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