Backyard Aquaponics
A place to discuss aquaponics

is there any reason that the grow beds have to be level or can they be higher at the non exit point ( or in other words the lower end being where it runs out back to the fish tank ) arpad

You want the water level to be 1" below the gravel line, so an uneven bed means your gravel would have to be uneven. What are you trying to accomplish?

I think he means does the top of the GB have to be level with the return tank, whether that be sump or fish tank.
If so, the answer is no.
The bottom of the GB (or the exit point) should be slightly (or more) above the top of the return tank.
But then it also depends on your system configuration, there are many options available.
As Kt asks, what are you trying to achieve?

as far as level, you want the growbed to be level, so that the water is distributed evenly throughout the bed

many thanks for everyones input ,