I found a partial list of the chemicals commonly used in pool water maintenance, and it illustrates the complexity of trying to filter them out. This came from the Morris County Municipal Utilities Authority, NJ website:

"A partial list of pool chemicals includes chlorinated isocyanurates, lithium hypochlorite, sodium bicarbonate, potassium monopersulfate, hydrogen peroxide, sodium hypochlorite , calcium hypochlorite, and certain ammonium, brominated, copper and silver compounds, and muriatic acid."

Perhaps none of these chemicals are harmful in the concentrations found in a home pool, but I do not want to be the one to find out!