Be careful with a crucible that full. It's very easy to spill. It was not shown but after you pour, put the crucible back in the furnace and allow out to cool naturally. Nice lifting tongs and pouring handle! The graphite is interesting. Make sure to wipe it out from the interior before heating as to not have it included in the melt

The dark spots and voids tell me that you didn't use flux,. or the right flux or not enough. Another way to avoid this and the ingot defects is to use a thick steel mold and preheat it until totally hot at the top opening of the kiln for several minutes before the pour.

Interesting! Research a proper flux for aluminum. When setting up, break and crush a dark brown bottle. add a couple of teaspoons of crushed glass in the crucible, then add scrap aluminum. The glass will assist the melt flow.