We have a saltwater chlorinated pool which a washed sand finish on the area around it,on the bond beam between the edge of the pool and water return moat there is a salt stain in a couple of high spots where the water doesn't flow continually into the moat. We've tried bleach/chlorine/detergent etc with vigorous brushing to no avail,anyone got a bright idea ?

Hi , Try HCl......hydrochloric acid.....strong as you can get....and paint it on with a paint brush. Handle the acid with great care. Then rinse ...with water from the pool.