question 1.) because of the movement of the water through the sand at a specified rate, each bacteria can grow on each grain of sand as more oxygen supplied water is flowing over them.
2.)Best bio filter- Imagine all the surface area on all that sand. Each Grain holds an area for the bacteria to live on and you have more then one grain of sand..so it can hold the most bacteria.
B.) I have a 1 year old tank. Good. Established. If I buy another one. The second tank will need to be cycled. correct? yes. WHOOOO. Hold the bus. What if I MOVED the FBF from the OLD tank to the NEW tank. WHOOOO.. now the NEW tank will have a LOAD of ood bacteria so you can immediatly add fish.
I hope you can understand that slip.