You know if you have enough filtration when
1) If you test for ammonia and nitrite, using a liquid test kit, and both are 0ppm (after cycling of course)
2) Rinsing the media in old tank water doesn't cause the tank to go cloudy and/or have a mini-cycle
3) You can fill the tank directly with water and water conditioner (at full tank dosage) after remove the old tank water and not have it go cloudy and/or have a mini-cycle
4) Your finish aren't breathing rapidly
I don't really care about particulate or debris on the bottom of the tank, but if you do
5) Not enough water movement on the bottom to blow the debris to the filter intake.
Oh good deal regarding the filtration. Im checking all those boxes.
Thanks!