Stained yellow stock bricks below granite paving

[Joni]

I have had a new granite patio laid using easy joint pointing. The patio is raised and sits on a base of yellow stock bricks. A few months in and a white deposit has stained the yellow bricks which I thought was salt deposits. But I have used Salt Away chemical that hasn't touched it, I'm wondering if the Easy Joint mixed with salt has caused the staining, making it really difficult to shift. I am resorting to a drill with wire brush attachment, but this is really long winded, does any body have any other ideas?

[lutonlagerlout]

almost certainly efflorescence
it will go with time
wire brush is to be avoided
LLL

[Joni]

Thanks LLL for your response.

A couple more questions..
Would efflorescence come from old London stocks or the cement behind the bricks? or easy joint?

Also, why if it is efflorescence, Salt Away hasn't removed it?
Thanks for your advice
Best wishes.