In my never-ending quest to find more effective biological filtration for QT use, I decided to give Seachem Matrix a try. Using Matrix inside the Seachem Tidal HOB powerfilter, I tested for copper absorption using Cupramine, Coppersafe & Copper Power in 3 different tanks. To my amazement, absorption was almost nonexistent. Only a very slight drop w/Cupramine (0.5 ppm) and no noticeable change with the two chelated coppers (2.0 ppm). I used the Chemetrics copper test kit to test all 3 tanks, before & after: https://www.chemetrics.com/index.php?route=product/product&product_id=392 So, next I reached out to Seachem about this and below is their response: Does anyone else have an experience to share regarding Seachem Matrix??