white stains on stone chimney

[mas3372 14]

I did a res. house last week and the customer was very happy. He had a beautiful stone chimney on the outside of the house that he spent some bigbucks for to add to the curb appeal. On it however is a huge white stain that covers about 1/4 of the chimney covering many of the stones and some mortor. He said it has been their since the chimney was one year old and has not improved or worsened. I would love to be able to make his day and call up and say "I found out how to get rid of that stain for you". He believes it is a calcium stain or something like that. I have no idea.

Any thoughts as to what it might be and how to get rid of it.

As always, thanks.

Mike

[Tronman 14]

Is there a water source near? Sprinkler, etc? If it is lime it will have either a flat white layer appearance or a rocky white pepple appearance. Another possibility is that it is grout from when the chimney was built - simple sulfamic or phosphoric acid wash. If it is lime - good luck. I have tried Hydrochloric, Muratic, Phosphoric, Mineral Shock, turbo blasting at 4,000psi, Calcite presoak, NMD80, etc. The only thing I have not tried is Effortless from EcoChem. I had good luck with the Calcite presoak, NMD 80, and a wire brush on a house a week ago but it took three trips and applications to get the calcium off of the beige brick.

Houston, Texas