On Mon, 21 Apr 2008 00:57:10 GMT, Erma1ina
wrote:

Check out

"How To Acid-Wash a Swimming Pool"

http://www.ehow.com/how_2005488_acid-wash-pool.html

or

"Pool Tip #20: Acid Washing"

http://www.alisonosinski.com/pooltips/20.htm

They recommend sodium carbonate (aka soda ash).

Thanks. the second link suggest a pre-post acid wash using TSP and
water. I like that suggestion.