PP will burn out the organics and pheromones as well but what it will not do is give the water the quality that a change-out with fresh water would have. Add to that the nitrates, added GH and other chems that may remain along with any components formed from the PP dose.
I suppose if you lived on Grand Crocodile Island needed to truck in your water for each change out and the ship with the water for your island had sank (did I mention men from Mars yet?) Then this would be an alternative. But I believe in most cases the PP and the power needed top pump the water from one vessel and into another and then back again would cost more than the water you where treating. So what is the point?