I know that pristine blue does not have a good rep here, but that's what we have to use. My daughter has reactions to chlorine (even the amount in the city water sometimes) so we CANNOT use it. We use pristine blue in our pool. It is vinyl, and we only have it up from late May until August. We purchased a sand filter this year. Can you please make a reccomendation for a NON chlorine sanitizing agent (and it cannot have artificial colors or smells), and also just any general guidelines to help us keep this thing clear and safe?