Can anyone kindly advise how to avoid the floating soil from landing on the plant's leaves as when the fish moves around, it will leave tiny debris of soil when accumulated on it.
You could try packing down your soil, then covering in gravel or sand. Try to avoid soils with floating debris like twigs or perlite. Over time, it should settle. Also, if your fish are diggers, they tend to not be good candidates for a dirted tank
Water flow in a big aquarium is mainly done for 3 reasons...
1. It keeps the water from settling on top which can cause a foul odor like say a smelly pond outside has that nasty smell to it...
2. Water flow helps to keep the tanks temperature even, so I live in Colorado which means winter gets cold here, so the water flow spreads the tanks temperature so it stays even around the entire tank.
3. Water flow helps to spread any fertilizers you're dosing around the tank as well...