Robertsoni are also a sand sifter of sorts, so it probably would see the geo's as direct competition. Most centrals in general will be rough on geos, even the most peaceful centrals still rate as much more territorial than your average SA cichlid.
As mentioned, you wouldn't want anything else on the bottom of the tank. Angels would be the best 'other' cichlid in a tank that size. If you end up upgrading later on, you can then think of adding others.
As mentioned, you wouldn't want anything else on the bottom of the tank. Angels would be the best 'other' cichlid in a tank that size. If you end up upgrading later on, you can then think of adding others.