I have a 10 gallon aquarium setup.... well had it setup. I decided to replace my 10 gallon Q tank with a 30 gallon Q tank. After the 30 gallon was set up, I turned off heater/filtration, and just kinda let the empty tank sit. I was lazy about cleaning it out. A week or so later, I turned on the light just for kicks, and saw all these thousands of tiny white specks swimming around. Any idea what these are? how did they get there?