I have a filter pad tray on my 400 gallon system that currently has poly-fil but I am looking for something bulk since I go through a lot and it gets expensive.. I see a lot of big 50ft polyester quilt batting rolls on amazon, but It is hard to tell which ones are safe for aquariums since most of them have no mention of being fire retardant or having other chemicals. Same with coolant filter paper. I'm looking for anything between 50 - 200 microns. Does anyone have a link for a big filter roll that they use that has been safe.