The pool guy just left after installing our light & he said that we have a film on the top of our water from using store brand bleach instead of actual pool chlorine. He said it's from soap that's in the bleach. I'm assuming that's not true since using bleach is one of the basic things that TFP recommends. Is what he said just baloney or am I using a bad kind of bleach? I am using Walmart's 8.25% 121 oz. basic stuff.