It depends on your water. If I'm right about your 'sock - it' it is calcium hypochlorite ~65% available chlorine. If you have a concrete pool and your CH test shows you need more, it's no problem. However, bleach doesn't add 'unwanted' stuff to the pool and usually costs less than a 'pool product' that adds the same amount of chlorine. As has been advocated elsewhere on this site, bleach is the way to go, unless you could stand to have some more (calcium, cya, etc) in the water.