PRETTY SURE THE SICCE SDC 6.0 IS HUGE FOR A 20 GALLON UNLESS YOU HAVE A BASEMENT SUMP OR SOMETHING.
Also, sorry for the caps.
Just realized thats an AIO tank?
If it is, I know nothing of AIO tanks/pumps, but the sicce 6.0 is way oversized, and I doubt it would fit in the pump area