Yes...you are creating a 'Plenum' it will definitely work,but you need 2 layers of sand seperate by a layer of mesh(to prevent critters from borrowing right through)Ideally bottom layer sand 00 and upper layer sand 02 or 03.It will be better if you raised the egg crate my means of tying 1" pvc pipes underneath the crate.
Light Emitting Diode hence LED is not a new technology it was invented abt 150 yrs ago.Some media even hailed it as the fourth most important discoveries aft the WHEEL.Intially it only emits altraviolet but through the years,many inventor have improved and enhance it to produce difference colour spectrums
LED have many advantages over Metal Halide or Incandescent light soucres;
1) lower energy consumption
2) longer lifetime
3) improved physical robustness
4) smaller size and lastly faster switching.
Imagine 'IF' every countries were to switch to using LED or using ( less or Free Energy).then we're are using less fossil fuel
hence saving our MotherEarth.
bioballs and filterwool will not produce nitrates if they stayed submerged.For cleaning,remove it and wash with water from the same tank.
Wet and dry filtration harbours difference bacteria,the latter actually produce nitrate aft consuming nitrite and the one submerge eliminate
nitrate.