I turned my filters off to clean. I cleaned then turned my filters back on and a bunch black specks ended up all over my sand. I thought it was coming from my filters. So I turned them back off and cleaned all the black specks out and then rinsed the filter media in the tank water. Replaced the water in the aquarium and turned the filters back on and they spit out a bunch of black specks again!! What do I need to do? I have an aquaclear 110 that has a sponge media, then carbon media, then ceramic media. And I have a marineland penguin bio wheel 200 that has a sponge and the wheel. What am I not doing right? Please help me!