I run two gunite pools at the gym I work at and I am planning on draining and cleaning them at the beginning of August. Last year when we drained them, we did muriatic acid wash for each pool. However, my general manager says that at the last place he worked (which also has gunite pools) they cleaned the pools with liquid chlorine and only used muriatic acid on the stains that did not come off with chlorine. Any advice on which method is preferable?