Well darn. Until you mentions color change. I run poly in my sock to catch extra materials. I did not realize it was specific to a special material. “Just learned something new today”. Having one shipped now. Won’t hurt at this point. Sps just keep dying. It has slowed but definitely not stopped. The strongest are now failing. And the brown outs are losing flesh slower.
Polyfilter brand pads are much different than polyester fiber filter medium, if that is what you were running.
Polyfilter brand pads are coated in a type of resin that pulls heavy metals, medications and toxins from the water.