just had a contractor replaster and tile my pool. im filling it up slowly as he recommended. i was told by the pool store not to add shock at first but to put in 6 bottles of acid. then one bottle per day for 15 days, brushing the sides 2x day. is this correct? he says the acid cures the plaster....but will it dissipate so its not harmful? and doesnt it eat the new colored plaster?