Please help - White glaze like staining on flagstones

[cleaner drive]

hello i am having problems cleaning a large stain from some flagstones, these flagstones are on my front step which is directly under my sandstone porch columns above the columns is the sandstone balcony. when i look up there seems to be what i can only describe is icicals or stalamites forming they just hang there it has been like this ever since i moved in.
now it is really bugging me and i want rid of these problems.
please help.
ps the stains are white and look kind of glazed over.

[Tony McC]

Sounds like lime bloom from the brickwork mortar.

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