Has anyone used Seachem matrix? I think it is a nitrate sponge. I pulled my out and wow it was so dirty after 6 months i threw it away. It started leaching back into trank and causing the water to be foamy. I liked to never figured what was causing this. Should have known better to keep things simple with good rock and skimming. After years of reefkeeping i should have let things be and not tried doing this.oh: