Having built an ATS,thanks to SM 1000 model,with a screen ordered from eBay,and run for few days, I found that the screen starts to become of brown color.(I have a lot of brown algae in my display tank).I wonder if this is useful for filtration and for how long it will become green ? By the way, I,ve stopped using Na3 and Ph removers the 1st day and to-day, I decide to cut the refugium filtering ( removing weed and cut lighting ). Will this help ?