I have a blue substance on my filter when I take it out to clean it. The pool chemicals are all in balance. I have an automatic cholorinator that has a blueish color plastic tube that holds the chlorine tablets in the chlorinator. Any chance it could be from that? I also have a pool heater, so I am wondering if the warm water is causing the color of the plastic to bleed. I attached a couple of pictures. Any thoughts? I just want to make sure this isn't something harmful to my equipment or people.