Tough stains

Anyone have advice on getting rid of some really tough stains on the vertical face of a waterfall?

I know that "elbow grease" is the most effective...but check out the attached pic.  That wall has already been treated with full-strength muriatic acid, and scrubbed with a steel brush. 

I know that there are chems that will prevent this type of build-up, but in the meantime, any suggestions?3423661000?profile=original

Horn Pool 2.jpg

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  • clr will clean that

    • clr!  I had forgotten about that stuff.  I'll give it a try.  Thank you!

  • I think you may have nailed it.  There is, indeed, a resevoir directly behind the wall, and the salt "stalagtites" forming on the surface are similar to the examples shown on wikipedia.  I have been averse to using any chemical that could affect water chemistry, but it appears that I will be contacting stone suppliers to discuss options.  Thank you for your help!

  • Stu

    It appears to be efflorescence. Essentially it's the salts trying to work out of the mortar.I would not advise straight acid as it will break down the integrity of any cement/mortar.

    When the stone work was done initially, a waterproofing agent should been applied to the surface where the stone is, and I suspect there is a well/resevoir where the water eminates from behind. That too should have been treated.

    An additive to the mortar should been added as well.

    Most stone suppliers carry cleaners to aid in removing efflorescence. Just be aware of their affect on your water chemistry or the finish on the pool.

    Here's the definition and a better scientific explanantion of this occurence. Good Luck!



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