I recently set up a new 75gallon FOWLR, and have a BS-1 Berlin sump from Marine Depot hooked up to it. My question is, I have the filter sock that comes with it hooked up, and I wash and change the filter out every 3-4 days. Do I need this sock and can it actually hurt my water quality? I like how clean and sparkling the water is because of it, but does it raise nitrates or other poisons? It just seems that since this tank started I have had problems with ich and now my flagfin has popeye. Maybe its just from stress of switching tanks in the last couple months. I dont know, anyway, what are your thoughts on the filter socks?