Cal build up swimming pool

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olive
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Cal build up swimming pool

Postby olive » Wed Jun 08, 2022 11:55 am

Perennial problem. Our tiles around the water line are quite badly stained with a build up of cal over the years.

We have tried Mercadona acid ( agua fuerte) . It doesn’t touch it and is quite difficult to apply on vertical surfaces. We have experimented with applying with a spray and then putting cling film on. Not having much effect.

An alternative would be to take the top 15 cm or so of tiles off all the way round, plus the top step and apply new. Would be time consuming but would look good when completed. Apart from cost and manhours, the only difficulty would probably be the “ cutting the grout “ betwen retained tiles and the ones to be removed.

A big step. Before embarking on that, has anyone seen or used products and tools that would remove the existing cal please? The internet has a chap with a glass bead machine- I-guess like a sand blaster!

ashtondav
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Re: Cal build up swimming pool

Postby ashtondav » Wed Jun 08, 2022 1:27 pm

I’m very surprised aqua fuerte doesn’t get rid of the cal. Have you been using a very stiff pool specific brush? Or just a scrubbing brush. It certainly dissolves it off every other surface. Can’t comment on other options

olive
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Re: Cal build up swimming pool

Postby olive » Wed Jun 08, 2022 4:33 pm

I think there are two types of cal.

Calcium Carbonate. Easy to remove with acid.

Calcium Silicate. Much tougher. Unfortuneately over the years we have had to leave the water without treatment for long periods of time eg family illnesses. Getting the PH right then chlorine levels on our return.

Googling suggests using a wet pumice stone and lots and lots of scrubbing. Other countries have chemicals for the problem . I was hoping someone on the forum knew of a chemical.

El Cid
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Re: Cal build up swimming pool

Postby El Cid » Wed Jun 08, 2022 5:39 pm

Is it actually cal? If it is it wouldn’t just be on the waterline. It’s more likely to be a mixture of oil and dirt. I would use a wire brush.

Sid

olive
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Re: Cal build up swimming pool

Postby olive » Wed Jun 08, 2022 7:51 pm

Yes , I am 99% certain it is calcium silicate. Lots of problems with it in other countries. Commercial solutions include blasting with tiny glass beads. DIY solutions include a low speed wet attachment on a battery powered drill. I guess that mimics a pumice stone. Just the right amount of abrasion. I will buy a pumice stone tomorrow and give that a try.

There is a chemical additive and you overfill the pool so the deposit is immersed. It dissolves it over the off season……… A non starter but a possible for winter coming.


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